#include <iostream>
using namespace std;

long long gcd(long long a, long long b){
    if (b == 0) return a;
    return gcd(b, a % b);
}

long long N, A, B;

int main() {
    cin >> N >> A >> B;
    long long L1 = N / A;
    long long L2 = N / B;
    long long M = gcd(A, B);
    long long L3 = L1 / (B / M);
    cout << L1 + L2 - L3 + 1 << endl;
    return 0;
}