#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

long long lcm(long long a, long long b) {
  return a / gcd(a, b) * b;
}

// override function template of std::lcm
long long lcm(int a, int b) {
  return lcm((long long)a, (long long)b);
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  long long t, a, b;
  cin >> t >> a >> b;

  long long c = lcm(a, b);
  
  long long ret = (t-1)/a + 1 + (t-1)/b + 1;
  ret -= (t-1)/c + 1;

  cout << ret << endl;
  
  return 0;
}