/* -*- coding: utf-8 -*-
 *
 * 894.cc:  No.894 二種類のバス - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

template <typename T>
T gcd(T m, T n) {  // m > 0, n > 0
  if (m < n) swap(m, n);
  while (n > 0) {
    T r = m % n;
    m = n;
    n = r;
  }
  return m;
}

/* main */

int main() {
  ll t, a, b;
  scanf("%lld%lld%lld", &t, &a, &b);

  ll g = gcd<ll>(a, b);
  __int128 l = (__int128)a * b / g;

  ll c = (t + a - 1) / a + (t + b - 1) / b - (t + l - 1) / l;
  printf("%lld\n", c);
  return 0;
}