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

int main() {
    long long T, A, B;
    cin >> T >> A >> B;
    long long ans = (T + A - 1) / A + (T + B - 1) / B - (T + lcm(A, B) - 1) / lcm(A, B);
    cout << ans << endl;

    return 0;
}