#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios::sync_with_stdio(false); cin.tie(0);
  long long t, a, b;
  cin >> t >> a >> b;
  long long lcm = a / __gcd(a, b) * b;
  long long x = t / a + (t % a > 0);
  long long y = t / b + (t % b > 0);
  long long z = t / lcm + (t % lcm > 0);
  cout << x + y - z << '\n';
  return 0;
}