#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

int main() {
    int A, B;
    cin >> A >> B;

    for (int i = -1000; i <= 1000; i++) {
        for (int j = 0; j < abs(B); j++) {
            if (A == B * i + j) {
                cout << j << endl;
                return 0;
            }
        }
    }
}