text: #include<iostream>
  using namespace std;
  int countSetBit(int n){
  	int ans=0;
  	while(n>0){
        n= n&(n-1);
        ans++;
  	}
  	return ans;
  }
   int main()
   {
   	int n=13;
   	cout<<countSetBit(n);
   	cout<<endl;
   	cout<<__builtin_popcount(n)<<endl;
  
   }