#include<iostream>
using namespace std;
using ll = long long;

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

int main() {
    ll t,a,b;
    cin >> t >> a >> b;
    ll ans = t/a + t/b;
    ans -= (t/a)/(b/gcd(a,b));
    cout << ans << endl;
}