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

#define rep(i, n) for (int i = 0; i < (int)n; i++)
using ll = long long int;

ll euclidean(ll a, ll b) {
  ll x, y;
  if (a > b) {
    x = a;
    y = b;
  } else {
    x = b;
    y = a;
  }
  while (x % y != 0) {
    ll z = y;
    y = x % y;
    x = z;
  }
  return y;
}

int main() {
  ll n, a, b;
  cin >> n >> a >> b;
  ll ai = n / a;
  ll bi = n / b;
  ll ab = n / (a * b / euclidean(a, b));
  cout << n - (ai+bi-ab) << endl;
  return 0;
}