#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ALL(a) (a).begin(), (a).end()
#define endl '\n'

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    long N, A, B;
    cin >> N >> A >> B;
    if (A == 1 || B == 1) {
        cout << 0 << endl;
        return 0;
    }
    long tmp = lcm(A, B);
    long mul = N / A + N / B - N / tmp;
    long ans = N - mul;
    cout << ans << endl;

    return 0;
}