using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;

class Program {
    static string ReadLine() { return Console.ReadLine(); }
    static int ReadInt() { return int.Parse(ReadLine()); }
    static int[] ReadInts() { return ReadLine().Split().Select(int.Parse).ToArray(); }
    static string[] ReadStrings() { return ReadLine().Split(); }

    static void Main() {
        var n = BigInteger.Parse(ReadLine());
        int ans = 0;
        foreach (var a in n.ToByteArray()) {
            /*
            int x = a;
            while (x > 0) {
                if ((x & 1) != 0) ans++;
                x >>= 1;
            }
            */
        }
        Console.WriteLine(ans);
    }
}