package Others;

import java.util.Scanner;

/**
 * @author Nishita Aggarwal
 * <p>Brian Kernighan’s Algorithm
 * <p>algorithm to count the number of set bits in a given number
 * <p>Subtraction of 1 from a number toggles all the bits (from right to left) till the
 * rightmost set bit(including the rightmost set bit). So if we subtract a number by 1 and do
 * bitwise & with itself i.e. (n & (n-1)), we unset the rightmost set bit.
 * <p>If we do n & (n-1) in a loop and count the no of times loop executes we get the set bit
 * count.
 * <p>
 * <p>Time Complexity: O(logn)
 */
public class BrianKernighanAlgorithm {

 /**
 * @param num: number in which we count the set bits
 * @return int: Number of set bits
 */
 static int countSetBits(int num) {
 int cnt = 0;
 while (num != 0) {
 num = num & (num - 1);
 cnt++;
 }
 return cnt;
 }

 /** @param args : command line arguments */
 public static void main(String args[]) {
 Scanner sc = new Scanner(System.in);
 int num = sc.nextInt();
 int setBitCount = countSetBits(num);
 System.out.println(setBitCount);
 sc.close();
 }
}