CLIPLX_author.java

import java.io.*;
import java.util.*;
class CLIPLX
{
    public static void main(String args[])throws IOException
    {
        Scanner in=new Scanner(System.in);
        int t=in.nextInt();
        while(t-->0)
        {
            int x=in.nextInt();
            int y=in.nextInt();
            System.out.println((int)Math.max(0,x-y));
        }
        
    }
}