#include "bits/stdc++.h"
using namespace std;

long long  gcd(long long  a, long long  b) {
	if (b == 0) return a;
	return gcd(b, a%b);
}

int main() {
	long long a, b;
	cin >> a >> b;
	cout << a / gcd(a, b) - 1 << endl;
}