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


signed main(){
    long long t, a, b;
    cin >> t >> a >> b;

    __int128 tt, aa, bb;
    tt = t;
    aa = a;
    bb = b;

    __int128 x = __gcd(a, b);

    __int128 l = aa / __gcd(a, b)  * bb;

    tt--;
    long long ans = tt/a + tt/b - tt/l + 1;

    cout << ans << endl;

    return 0;
}