#include<bits/stdc++.h>
using namespace std;

int main()
{
    /*   ///problem 2
    int t;
    cin>>t;
    while(t--){
        string S;
        cin>>S;
        int Q;
        cin>>Q;

        deque<char> dq(S.begin(), S.end());
        bool isReversed=false;

        while(Q--){
            int queryType;
            cin>>queryType;
            if(queryType == 1){
                isReversed=!isReversed;
            }
            else if(queryType == 2){
                int D;
                char C;
                cin>>D>>C;
                if(isReversed){
                    if(D==1){
                        dq.push_back(C);
                    }else{
                        dq.push_front(C);
                    }
                }else{
                    if(D==1){
                        dq.push_front(C);
                    }else{
                        dq.push_back(C);
                    }

                }
            }
        }
        if(isReversed){
            reverse(dq.begin(),dq.end());
        }
        for(char c: dq){
            cout<<c;
        }
        cout<<endl;

        */

        int t;
        cin>>t;
        while(t--){
            long long N,K;
            cin>>N>>K;
            if(K<N){
                cout<<0<<endl;
                continue;
            }
            long long X = K-N;
            long long Y = 1;
            cout<<X*Y<<endl;
        }

    return 0;
}