#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;
typedef long long int ll;

long long GCD(long long a, long long b) { return b ? GCD(b, a%b) : a; }

int main(){
    ll t,a,b; cin >> t >> a >> b;
    ll ans=0;
    ans+=(t+a-1)/a;
    ans+=(t+b-1)/b;
    if((double)a/GCD(a,b)>=(double)t/b){
        ans--;
        cout << ans << endl;
        return 0;
    }
    else{
        ll Lcm=a/GCD(a,b)*b;
        ans-=(t+a/GCD(a,b)*b-1)/(a/GCD(a,b)*b);
    }
    cout << ans << endl;
}