#include <iostream>
#include <cmath>
using namespace std;

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

long long T, A, B;

int main() {
	cin >> T >> A >> B; T--;
	long long C = gcd(A, B), D = 1;
	long double F1 = log10(1.0L*A), F2 = log10(1.0L*B), F3 = log10(1.0L*C);
	if (F1 + F2 - F3 > 18.5) {
		D = 1;
	}
	else {
		D = 1LL + T / (A*B / C);
	}
	long long E1 = T / A + 1, E2 = T / B + 1;
	cout << E1 + E2 - D << endl;
	return 0;
}