#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

inline ll satulating_lcm(ll a, ll b) {
  ll g = gcd(a, b);
  constexpr ll INF = 4e18;
  if (a / g > INF / b) return INF;
  return a / g * b;
}

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  ll t, a, b;
  cin >> t >> a >> b;
  ll ans = 0;
  ans += (t + a - 1) / a;
  ans += (t + b - 1) / b;
  ans -= (t + satulating_lcm(a, b) - 1) / satulating_lcm(a, b);
  cout << ans << '\n';
  return 0;
}