#include <bits/stdc++.h>

int main()
{
	std::cin.tie(nullptr);
	std::ios::sync_with_stdio(false);
	
	uint_fast64_t N;
	uint_fast32_t A, B;
	std::cin >> N >> A >> B;

	std::cout << N - (N / A) - (N / B) + (N / std::lcm<uint_fast64_t, uint_fast64_t>(A, B)) << '\n';
	return 0;
}