#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll gcd(ll a,ll b){
  if(b==0){
    return a;
  }
  return gcd(b,a%b);
}
int main(){
  ll t,a,b;cin >> t >> a >> b;
  t--;
  ll c=a/gcd(a,b)*b;
  if(c>0){
    cout << t/a+t/b-t/c+1 << endl;
  }
  else{
      cout << t/a+t/b+1 << endl;
  }
}