Problem:
Score : 100 points

Problem Statement

Snuke has a grid consisting of three squares numbered 1, 2 and 3.
In each square, either 0 or 1 is written. The number written in Square i is s_i.

Snuke will place a marble on each square that says 1.
Find the number of squares on which Snuke will place a marble.

Constraints

Each of s_1, s_2 and s_3 is either 1 or 0.

Input

Input is given from Standard Input in the following format:

s_{1}s_{2}s_{3}

Output

Print the answer.

Sample Input 1

101

Sample Output 1

2

A marble will be placed on Square 1 and 3.

Sample Input 2

000

Sample Output 2

0

No marble will be placed on any square.

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;

namespace atcoder_practice1
{
    class _081A
    {
        static void Main()
        {
            string str;
            int count = 0;
            str = Console.ReadLine();

            for(int i=0; i < str.Length; i++)
            {
                if(str[i] == '1')
                {
                    count++;
                }
            }
            Console.WriteLine(count);
        }
    }
}