#include <fstream>

using namespace std;
ifstream fin ("euclid3.in");
ofstream fout ("euclid3.out");
int gcd (int a, int b, int &x, int &y)
{
    int x0, y0, d;
    if (b == 0)
    {
        x = 1;
        y = 0;
        return a;
    }
    d = gcd (b, a % b, x0, y0);
    x = y0;
    y = x0 - (a / b) * y0;
    return d;
}
int main()
{
    int A, B, X, Y, i, n, c, D;
    fin >> A >> n;
    D = gcd (A, n, X, Y);
    X = X * D;
    while (X < 0)
        X += n;
    fout << X;
    return 0;
}