#include <iostream>
#include <cmath>
using namespace std;
int a,b,a2,b2, wynik, ile;
int main()
{
cin>>ile;
for(int i=1; i<=ile; i++)
{
cin>>a>>b;
if(b==0)
{
cout<<endl;
}
else
{
a2=fabs(a);
b2=fabs(b);
wynik=a%b;
cout<<wynik<<endl;
}
}
return 0;
}
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