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

int main() {
    int a, b;
    cin >> a >> b;
    int q = a / b;
    a -= b * q;
    if (0 <= a && a < abs(b)) {
        cout << a << endl;
    } else if (a < 0) {
        while (a < 0) {
            a += b;
        }
        cout << a << endl;
    } else {
        while (abs(b) <= a) {
            a -= b;
        }
        cout << a << endl;
    }
}