#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000086, MOD = 1e9 + 7, INF = 0x3f3f3f3f;
ll res;
int n, m, cnt, w[N];


int main() {
    ll n, a, b;
    cin >> n >> a >> b;
    if (a == b) {
        printf("%lld\n", n - n / a);
        return 0;
    }
    ll v1 = n / a, v2 = n / b, v3 = n / (a * b / __gcd(a, b));
    printf("%lld\n", n - v1 - v2 + v3);
}