#include <iostream>
#include <vector>

using namespace std;
using ll = long long;

constexpr int iINF = 1'000'000'000;
constexpr ll llINF = 1'000'000'000'000'000'000;

int main () {
    int A, B; cin >> A >> B;
    B = abs(B);
    int res = A % B;
    if (res < 0) res += B;
    cout << res << "\n";
}