#include <iostream>

using namespace std;
typedef long long ll;

ll gcd(ll a, ll b){
    if(a < b) swap(a, b);
    while(b != 0){
        ll tmp = b;
        b = a%b;
        a = tmp;
    }
    return a;
}

ll lcm(ll a, ll b){
    return ((a/gcd(a, b))*b);
}

int main(){
    ll T, A, B;
    cin >> T >> A >> B;
    ll ans = 1+(T-1)/A + (T-1)/B;
    ll m = gcd(A, B);
    if(A/m > T/B){
        cout << ans << endl;
    }else{
        ans -= (T-1)/lcm(A, B);
        cout << ans << endl;
    }
}