AWS cloudeformation Create VPC+Instance(2 pubulic subnet and 2 private subnet and 1 instance in PubAsub)

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description" : "Creates an VPC, 2 public subnets, 2 private subnets, and an Amazon EC2 instance.EC2 instance is Amazon Linux and ts2.nano",
  "Parameters" : {
    "KeyName": {
      "Description" : "Name of an existing EC2 key pair for SSH access to the EC2 instance.",
      "Type": "AWS::EC2::KeyPair::KeyName"
    }
  },  
  "Resources": {
    "MainVPC": {
      "Type": "AWS::EC2::VPC",
      "Properties": {
        "CidrBlock": "10.0.0.0/16",
        "EnableDnsSupport": "true",
        "EnableDnsHostnames": "true",
        "InstanceTenancy": "default",
        "Tags": [
          {
            "Key" : "Application",
            "Value" : { "Ref" : "AWS::StackName"}
          }
        ]
      }
    },
    "InetGW": {
      "Type": "AWS::EC2::InternetGateway",
      "Properties": {
        "Tags" : [  
          {
            "Key" : "Application",
            "Value" : { "Ref" : "AWS::StackName"}
          }
        ]
      },
      "DependsOn": [
        "MainVPC"
      ]
    },
    "AttachInetGW": {
      "Type": "AWS::EC2::VPCGatewayAttachment",
      "Properties": {
        "InternetGatewayId": {
          "Ref": "InetGW"
        },
        "VpcId": {
          "Ref": "MainVPC"
        }
      },
      "DependsOn": [
        "MainVPC",
        "InetGW"
      ]
    },
    "PubAsub": {
      "Type": "AWS::EC2::Subnet",
      "Properties": {
        "VpcId": {
          "Ref": "MainVPC"
        },
        "CidrBlock": "10.0.1.0/24",
        "AvailabilityZone": {
          "Fn::Select": [
            "0",
            {
              "Fn::GetAZs": {
                "Ref": "AWS::Region"
              }
            }
          ]
        },
        "Tags": [
          {
            "Key" : "Application",
            "Value" : { "Ref" : "AWS::StackName"}
          },
          {
            "Key" : "Name",
            "Value" : "PubAsub"
           },          {
            "Key" : "Network",
            "Value" : "Public"
          }
        ]
      },
      "DependsOn": [
        "MainVPC"
      ]
    },
    "PubBsub": {
      "Type": "AWS::EC2::Subnet",
      "Properties": {
        "VpcId": {
          "Ref": "MainVPC"
        },
        "CidrBlock": "10.0.2.0/24",
        "AvailabilityZone": {
          "Fn::Select": [
            "1",
            {
              "Fn::GetAZs": {
                "Ref": "AWS::Region"
              }
            }
          ]
        },
        "Tags": [
          {
            "Key" : "Application",
            "Value" : { "Ref" : "AWS::StackName"}
          },
          {
            "Key" : "Name",
            "Value" : "PubBsub"
           },
          {
            "Key" : "Network",
            "Value" : "Public"
          }
        ]
      },
      "DependsOn": [
        "MainVPC"
      ]
    },
    "PrivateAsub": {
      "Type": "AWS::EC2::Subnet",
      "Properties": {
        "VpcId": {
          "Ref": "MainVPC"
        },
        "CidrBlock": "10.0.11.0/24",
        "AvailabilityZone": {
          "Fn::Select": [
            "0",
            {
              "Fn::GetAZs": {
                "Ref": "AWS::Region"
              }
            }
          ]
        },
        "Tags": [
          {
            "Key" : "Application",
            "Value" : { "Ref" : "AWS::StackName"}
          },
          {
            "Key" : "Name",
            "Value" : "PrivateAsub"
           },          {
            "Key" : "Network",
            "Value" : "Private"
          }
        ]
      },
      "DependsOn": [
        "MainVPC"
      ]
    },
    "PrivateBsub": {
      "Type": "AWS::EC2::Subnet",
      "Properties": {
        "VpcId": {
          "Ref": "MainVPC"
        },
        "CidrBlock": "10.0.12.0/24",
        "AvailabilityZone": {
          "Fn::Select": [
            "1",
            {
              "Fn::GetAZs": {
                "Ref": "AWS::Region"
              }
            }
          ]
        },
        "Tags": [
          {
            "Key" : "Application",
            "Value" : { "Ref" : "AWS::StackName"}
          },
          {
            "Key" : "Name",
            "Value" : "PrivateBsub"
           },
          {
            "Key" : "Network",
            "Value" : "Private"
          }
        ]
      },
      "DependsOn": [
        "MainVPC"
      ]
    },
    "InternetRouteTable": {
      "Type": "AWS::EC2::RouteTable",
      "Properties": {
        "VpcId": {
          "Ref": "MainVPC"
        },
        "Tags": [
          {
            "Key" : "Application",
            "Value" : { "Ref" : "AWS::StackName"}
          }
        ]
      },
      "DependsOn": [
        "MainVPC"
      ]
    },
    "InternetRote": {
      "Type": "AWS::EC2::Route",
      "Properties": {
        "RouteTableId": {
          "Ref": "InternetRouteTable"
        },
        "DestinationCidrBlock" : "0.0.0.0/0",
        "GatewayId": {
          "Ref": "InetGW"
        }
      },
      "DependsOn": [
        "AttachInetGW"
      ]
    },
    "PubSubRouteTableAssociationA" : {
      "Type" : "AWS::EC2::SubnetRouteTableAssociation",
      "Properties" : {
        "SubnetId" : { "Ref" : "PubAsub" },
        "RouteTableId" : { "Ref" : "InternetRouteTable" }
      }
    },  
    "PubSubRouteTableAssociationB" : {
      "Type" : "AWS::EC2::SubnetRouteTableAssociation",
      "Properties" : {
        "SubnetId" : { "Ref" : "PubBsub" },
        "RouteTableId" : { "Ref" : "InternetRouteTable" }
      }
    },  
    "WebSecurityGroup": {
      "Type": "AWS::EC2::SecurityGroup",
      "Properties": {
        "VpcId": {
          "Ref": "MainVPC"
        },
        "GroupDescription": "Allow access from HTTP and HTTPS traffic",
        "SecurityGroupIngress": [
          {
            "IpProtocol": "tcp",
            "FromPort": "80",
            "ToPort": "80",
            "CidrIp": "0.0.0.0/0"
          },
          {
            "IpProtocol": "tcp",
            "FromPort": "443",
            "ToPort": "443",
            "CidrIp": "0.0.0.0/0"
          }
        ]
      },
      "DependsOn": [
        "MainVPC"
      ]
    },
    "SSHSecurityGroup": {
      "Type": "AWS::EC2::SecurityGroup",
      "Properties": {
        "VpcId": {
          "Ref": "MainVPC"
        },
        "GroupDescription": "Allow access from SSH traffic",
        "SecurityGroupIngress": [
          {
            "IpProtocol": "tcp",
            "FromPort": "22",
            "ToPort": "22",
            "CidrIp": "0.0.0.0/0"
          }
        ]
      },
      "DependsOn": [
        "MainVPC"
      ]
    },
    "WebServer1" : {
      "Type" : "AWS::EC2::Instance",
      "Properties" : {
        "ImageId" : "ami-56d4ad31",
        "InstanceType" : "t2.micro",
        "KeyName" : { "Ref" : "KeyName" },
        "NetworkInterfaces": [
          {
            "AssociatePublicIpAddress": "true",
            "DeviceIndex": "0",
            "SubnetId" : { "Ref" : "PubAsub" },
            "GroupSet": [
              { "Ref" : "SSHSecurityGroup" },
              { "Ref" : "WebSecurityGroup" }
            ]
          }
        ],
      "BlockDeviceMappings" : [
        {
          "DeviceName" : "/dev/xvdb",
          "Ebs" : {
            "DeleteOnTermination": "true",
            "VolumeType" : "gp2",
            "Encrypted" : "false",
            "VolumeSize" : "20" 
          }
        }
      ],
        "Tags" : [
          {
            "Key" : "Application",
            "Value" : { "Ref" : "AWS::StackName"}
          },
          {
            "Key" : "Name",
            "Value" : "WebServer"
          }
        ]
      }
    }
  }
}