#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define rep(i, a, b) for (ll i = a; i < b; ++i)
#define rrep(i, a, b) for (ll i = a; i >= b; --i)

// --- 初期設定（入出力の高速化と小数15桁出力） ---
struct Init {
  Init() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);
  }
} init;
// ------------------------------------------------

int main() {
  int n, x, y;
  cin >> n >> x >> y;
  ll ans = 0;
  rep(i, 0, n + 1){
    if(i % x > i % y){
      ++ans;
    }
  }

  cout << ans << "\n";
  return 0;
}

// Pre-written library: https://github.com/ssmbc2929bartok/cp-env