#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-1)/A)+((T-1)/B);
  ll K = (T-1)/lcm_(A,B);
  ans -= K;
  cout << ++ans << '\n';
  return 0;
}