#include <iostream>
using namespace std;
unsigned int count_set_bits(unsigned int n) {
unsigned int count = 0;
while (n) {
count += n & 1;
n >>= 1;
}
return count;
}
int main()
{
int n = 45; // 00101101
cout << count_set_bits(n);
return 0;
}
/*
run:
4
*/