#include <bits/stdc++.h> 

using i64 = long long; 
using u64 = unsigned long long; 
using u32 = unsigned; 

using u128 = unsigned __int128; 
using i128 = __int128; 

void solve() {
	i64 T, A, B;
	std::cin >> T >> A >> B;

	i128 lcm = ((i128)A/ std::gcd(A,B)) * B;

	i64 ans = (T - 1) / A + (T - 1) / B;

	ans -= (T - 1) / lcm;

	std::cout << ans + 1 << "\n";
} 

int main() { 
	std::ios::sync_with_stdio(false); 
	std::cin.tie(nullptr); 

	int T = 1; 
	//std::cin >> T; 

	while (T--) { 
		solve(); 
	} 
	return 0; 
}