Convert number from any numeral system to any other with base between 2 and 16

AnyNumeralSystemConverter

//Write a program to convert from any numeral system of given base s to any other numeral system of base d (2 ≤ s, d ≤  16).

using System;
using System.Collections.Generic;
using System.Numerics;

namespace Task_7_AnySystemConverter
{
class Program
{
static void Main()
{
    Console.Write("Please enter INPUT base(2-16): ");
    string input = Console.ReadLine();
    int InputBase = 0;
    int OutputBase = 0;
    double Decimal = 0;
    string OutputReversed = "";
    string Output = "";

    while (int.TryParse(input, out InputBase) == false || InputBase < 2 || InputBase > 16)
    {
        Console.Write("Please enter a valid base from 2 to 16: ");
        input = Console.ReadLine();
    }

    Console.Write("Please enter OUTPUT base(2-16): ");
    input = Console.ReadLine();

    while (int.TryParse(input, out OutputBase) == false || OutputBase < 2 || OutputBase > 16)
    {
        Console.Write("Please enter a valid base from 2 to 16: ");
        input = Console.ReadLine();
    }

    Console.Write("Please enter {0} numeral system number: ",InputBase);
    input = Console.ReadLine();

    for (int i = 0; i < input.Length; i++)
    {
        switch (input[i])
        {
            case '0': Decimal += 0;
                break;
            case 'x': Decimal += 0;
                break;
            case '1': Decimal += Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case '2': Decimal += 2 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case '3': Decimal += 3 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case '4': Decimal += 4 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case '5': Decimal += 5 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case '6': Decimal += 6 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case '7': Decimal += 7 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case '8': Decimal += 8 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case '9': Decimal += 9 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case 'A': Decimal += 10 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case 'B': Decimal += 11 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case 'C': Decimal += 12 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case 'D': Decimal += 13 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case 'E': Decimal += 14 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            case 'F': Decimal += 15 * Math.Pow(InputBase, input.Length - 1 - i);
                break;
            default: Console.WriteLine("ERROR!");
                break;
        }
    }
    Decimal = Convert.ToInt32(Decimal);

    while ((int)Decimal > 0)
    {
        int Remainder = (int)Decimal % OutputBase;
        Decimal /= OutputBase;

        switch (Remainder)
        {
            case 0: OutputReversed += 0;
                break;
            case 1: OutputReversed += 1;
                break;
            case 2: OutputReversed += 2;
                break;
            case 3: OutputReversed += 3;
                break;
            case 4: OutputReversed += 4;
                break;
            case 5: OutputReversed += 5;
                break;
            case 6: OutputReversed += 6;
                break;
            case 7: OutputReversed += 7;
                break;
            case 8: OutputReversed += 8;
                break;
            case 9: OutputReversed += 9;
                break;
            case 10: OutputReversed += "A";
                break;
            case 11: OutputReversed += "B";
                break;
            case 12: OutputReversed += "C";
                break;
            case 13: OutputReversed += "D";
                break;
            case 14: OutputReversed += "E";
                break;
            case 15: OutputReversed += "F";
                break;
            default: Console.WriteLine("ERROR!");
                break;
        }
    }

    for (int i = OutputReversed.Length - 1; i >= 0; i--)
    {
        Output += Convert.ToChar(OutputReversed[i]);
    }

    Console.WriteLine("\nOUTPU: {0}\n", Output);
}
}
}