#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
long long gcd(long long a, long long b) {
    if (a % b == 0) {
        return (b);
    }
    else {
        return (gcd(b, a % b));
    }
}
int main() {
    long long n, d;
    cin >> n >> d;
    long long ans = n / gcd(n, d) * d;
    cout << ans / d - 1 << endl;
    return 0;
}