Closest number

#include<iostream>
#include<cmath>
using namespace std;

int main(){
    int t; cin >> t;
    while(t--){
        int n, m; cin >> n >> m;
        int big = n, small = n;
        while(big % m != 0) big++;
        while(small % m != 0) small--;

        if(n < 0) swap(big, small);

        int big_diff = abs(big) - abs(n);
        int small_diff = abs(n) - abs(small);
/*
        cout << big << ' ' << small << endl;
        cout << big_diff << ' ' << small_diff << endl;
*/

        if(big_diff < small_diff) cout << big << endl;
        else if(small_diff < big_diff) cout << small<< endl;
        else if(big_diff == small_diff) {
            int k = max(abs(big), abs(small));
            if(k == abs(big)){
                cout << big << endl;
            }
            else cout << small << endl;
        }

    }
}