#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("euclid2.in");
ofstream fout("euclid2.out");

int main()
{
    int a,b,r,T;
    fin>>T;


        for(int i=0;i<T;i++)
    {
        fin>>a>>b;
if(a>b)
{

        r=a-b;
         while(r>b)
         {
             r=r-b;
         }
          fout<<r<<endl;
}
 if(b>a)
    {
      r=b-a;
         while(r>a)
         {
             r=r-a;
         }
          fout<<r<<endl;
    }


    }
}