#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ul = unsigned long;
using ull = unsigned long long;

template <class T>
T gcd(T a, T b)
{
	return b == 0 ? a : gcd(b, a % b);
}

template <class T>
T lcm(T a, T b)
{
	T g = gcd(a, b);

	return a * b / g;
}

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

	ull t, a, b;
	cin >> t >> a >> b;

	ull l = lcm(a, b);

	ull res = (t + a - 1) / a + (t + b - 1) / b - (t + l - 1) / l;

	cout << res << "\n";

	return 0;
}