#include <bits/stdc++.h>
#define ll long long

using namespace std;

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

ll a, b, c, d, x, y;	

void euclid(ll a, ll b, ll &d, ll &x, ll &y){
	if(b == 0){
		d = a;
		x = 1;
		y = 0;
	} else {
		ll x0, y0;
		euclid (b, a % b, d, x0, y0);
		x = y0;
		y = x0 - y0 * (a / b);
	}
}

int main(){
	in >> a >> b;
	euclid(a, b, d, x, y);
	while(x < 0)
		x += b;
	out << x;
	return 0;
}