#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define repr(i, n) for (int i = (n) - 1; i >= 0; i--)
#define range(a) a.begin(), a.end()

using namespace std;
using ll = long long;

ll lcm(ll a, ll b) {
  ll g = __gcd(a, b);
  if (__builtin_mul_overflow_p(a / g, b, 0LL)) return 2e18;
  return a / g * b;
}

ll cquot(ll a, ll b) {
  return (a + b - 1) / b;
}

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  ll T, A, B; cin >> T >> A >> B;
  cout << cquot(T, A) + cquot(T, B) - cquot(T, lcm(A, B)) << endl;
}