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

using namespace std;

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

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

void gcd(ll a, ll b, ll &d, ll &x, ll &y){
	if(b == 0){
		d = a;
		x = 1;
		y = 0;
	} else {
		ll xx, yy;
		gcd(b, a % b, d, xx, yy);
		x = yy;
		y = xx - yy * (a / b);
	}
}

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