#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>
#define LP pair<ll, ll>

const ll INF = 1e18;

int main() {
  ll t, a, b;
  cin >> t >> a >> b;
  ll ans = (t-1)/a+(t-1)/b+2;
  ll g = gcd(a,b);
  if (a/g < INF/b) {
    ll l = a/g*b;
    ans -= (t-1)/l+1;
  } else {
    ans--;
  }
  cout << ans << endl;


  return 0;
}