Problem:
Score : 100 points

Problem Statement

You are given an integer N that has exactly four digits in base ten.
How many times does 2 occur in the base-ten representation of N?

Constraints

1000 \leq N \leq 9999

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer.

Sample Input 1

1222

Sample Output 1

3

2 occurs three times in 1222. By the way, this contest is held on December 22 (JST).

Sample Input 2

3456

Sample Output 2

0

Sample Input 3

9592

Sample Output 3

1

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


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

class Program
{
    static void Main(string[] args)
    {
        //List<int> values = new List<int>(Console.ReadLine().Split(' ').Select(s => int.Parse(s)));
        //List<int> values = new List<int>();

        string input = Console.ReadLine();
        //int n = int.Parse(input.Split(' ')[0]);
        //int m = int.Parse(input.Split(' ')[1]);
        //int k = int.Parse(input.Split(' ')[2]);

        int a = 0;
        foreach (var item in input)
        {
            if(item == '2')
            {
                a++;
            }
        }

        Console.WriteLine(a); return;



    }
}