#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 x = (t + a - 1) / a;
  long long y = (t + b - 1) / b;
  long long g = __gcd(a, b);
  long long z;
  if (1. * a / g * b >= 2e18) z = 1LL << 60;
  else z = a / g * b;
  z = (t + z - 1) / z;
  cout << x + y - z << '\n';
  return 0;
}