#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl "\n"

int exgcd(int a, int b, int &x, int &y) {
    if (!b) {
        x = 1, y = 0;
        return a;
    }
    int d = exgcd(b, a % b, y, x);
    y -= a / b * x;
    return d;
}

signed main() {
    int a, b;
    cin >> a >> b;
    int x, y;
    exgcd(a, b, x, y);
    cout << (x % b + b) % b << endl;
}