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

int main(){
    long long T, A, B;
    cin >> T >> A >> B;
    long long a, b, c, g;
    a = (T - 1)/A + 1;
    b = (T - 1)/B + 1;
    c = 1;
    g = __gcd(A, B);
    if (log(A) + log(B) - log(g) <= log(2e18)){
        c = (T - 1) / (A / g * B) + 1;
    }
    cout << a + b - c << endl;
    return 0;
}