Problem:
Score : 100 points

Problem Statement

Snuke prepared 6 problems for a upcoming programming contest.
For each of those problems, Rng judged whether it can be used in the contest or not.

You are given a string S of length 6.
If the i-th character of s is 1, it means that the i-th problem prepared by Snuke is accepted to be used; 0 means that the problem is not accepted.

How many problems prepared by Snuke are accepted to be used in the contest?

Constraints

The length of S is 6.

S consists of 0 and 1.

Inputs

Input is given from Standard Input in the following format:

S

Outputs

Print the number of problems prepared by Snuke that are accepted to be used in the contest.

Sample Input 1

111100

Sample Output 1

4

The first, second, third and fourth problems are accepted, for a total of four.

Sample Input 2

001001

Sample Output 2

2

Sample Input 3

000000

Sample Output 3

0

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

using System;
using System.Linq;

namespace Sample1
{
    class Program
    {
        static void Main(string[] args)
        {
            string input;
            int answer = 0;
            while (true)
            {
                input = Console.ReadLine();
                for(int i = 0; i < 6;i++){
                    int numb = Int32.Parse(input[i].ToString());
                    if(numb == 1)
                    {
                        answer++;
                    }
                }
                Console.Write(answer + "\n");
                answer = 0;

            }

        }
    }
}