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: Runtime Error)

using System;
class Program
{
	static void Main(string[] args)
	{
		// 整数の入力
		string[] str = Console.ReadLine().Split();
		int s1 = int.Parse(str[0]);
		int s2 = int.Parse(str[1]);
		int s3 = int.Parse(str[2]);

		// int s11 = int.Parse(Console.ReadLine(Read));
		// int s21 = int.Parse(Console.ReadLine(Read));
		// int s3 = int.Parse(Console.ReadLine(Read));
		int result = 0;
			if (s1 > 0)
			{
				result += 1;
			}
			if (s2 > 0)
			{
				result += 1;
			}
			if (s3 > 0)
			{
				result += 1;
			}
		Console.WriteLine(result);
	}
}