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

int main() {
    unsigned long long n, a, b;
    cin >> n >> a >> b;
    unsigned long long ans = n * (n + 1) / 2;
    int ak = n / a;
    ans -= a * (ak + 1) * ak / 2;
    int bk = n / b;
    ans -= b * (bk + 1) * bk / 2;
    int ck = n / (a * b);
    ans += a * b * (ck + 1) * ck / 2;
    cout << ans << endl;
    return 0;
}