#include <iostream>
using namespace std;

//最大公約数
int gcd(int n, int m) {
	if (m == 0)return n;
	return gcd(m, n%m);
}
//最小公倍数
int lcm(int n, int m) {
	int g = gcd(n, m);
	return n / g * m;
}

int main() {
	int n, d;
	cin >> n >> d;
	cout << n / gcd(n, d) - 1 << endl;
}