#include <bits/stdc++.h>
#define rep(i,a,b) for (int (i)=(a);(i)<(b);++(i))
#define sz(x) (x).size()
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
const int INF = 1e9;
const ll LINF = 1LL<<60;
const ll MOD = 1e9+7;

ll T,A,B;
ll gcd(ll a, ll b) {
  return a%b==0?b:gcd(b,a%b);
}
ll lcm(ll a, ll b) {
  return a/gcd(a,b)*b;
}

int main() {
  cin>>T>>A>>B;
  ll ans = (T+A-1)/A+(T+B-1)/B;
  ll l = lcm(A,B);
  ans -= (T+l-1)/l;
  cout << ans << '\n';
  return 0;
}