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