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

ll gcd(ll a, ll b){
    while(b != 0){
        ll r = a%b;
        a = b; b = r;
    }
    return a;
}

int main(){
    ll t, a, b;
    cin >> t >> a >> b;
    ll ans = (t+a-1)/a + (t+b-1)/b;
    ll g = gcd(a, b);
    if(b/g <= 1'000'000'000'000'000'000/a){
        ll l = a*(b/g);
        ans -= (t+l-1)/l;
    }else{
        ans--;
    }

    cout << ans << endl;
    return 0;
}