//#include <iostream>
#include <fstream>
using namespace std;

ifstream cin ("inversmodular.in");
ofstream cout ("inversmodular.out");

int gcd(long long a, long long b, long long& x, long long& y) {
    if (b == 0) {
        x = 1;
        y = 0;
        return a;
    }
    long long x1, y1;
    long long d = gcd(b, a % b, x1, y1);
    x = y1;
    y = x1 - y1 * (a / b);
    return d;
}

int main()
{
    long long a,n;
    cin>>a>>n;
    long long x, y;
    long long g = gcd(a, n, x, y);
    if(g==1)
    {
        x = (x % n + n) % n;
        cout << x;
    }
    return 0;
}