#include <bits/stdc++.h>
using namespace std;
int exGcd(int a, int b, int &x, int &y)
{
    if (b == 0)
    {
        x = 1, y = 0;
        return a;
    }
    int xx, yy;
    int gcd = exGcd(b, a % b, xx, yy);
    x = yy;
    y = xx - (a / b) * yy;
    return gcd;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int a, b, x, y;
    cin >> a >> b;
    int gcd = exGcd(a, b, x, y);
    cout << (x % b + b) % b << "\n";
    return 0;
}