#include <bits/stdc++.h>
using namespace std;
using lint = long long;
template<class T = int> using V = vector<T>;
template<class T = int> using VV = V< V<T> >;

int main() {
  cin.tie(nullptr); ios::sync_with_stdio(false);
  lint t, a, b; cin >> t >> a >> b;
  lint m = a / __gcd(a, b);
  m = m <= (t + b - 1) / b ? m * b : (lint)9e18;
  lint res = (t + a - 1) / a + (t + b - 1) / b - (t + m - 1) / m;
  cout << res << '\n';
}