#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

int main() {
	int n, d;

	cin >> n >> d;

	int gcd = __gcd(n,d);
	n /= gcd;
	d /= gcd;

	int ans = n % d == 0 ? n / d : n;
	ans--;
	cout << ans << endl;
	return 0;
}