#include<iostream>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<vector>
#include<map>
#include<queue>
using namespace std;
typedef long long ll;
const int MOD=1e9+7;
int main() {
  ll a,b,t,ans=0,g,l;
  cin >> t >> a >> b;
  ans+=(t-1)/a+1;
  ans+=(t-1)/b+1;
  g=__gcd(a,b);
  l=a/g*b;
  ans-=(t-1)/l+1;
  cout << ans << endl;
}