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;

public class AtCoder
{
    public static void Main()
    {
        string[] t;
        t = NextS();
        string s = t[0];
        int n = 0;
        if (s.Substring(0,1) == "2") n++;
        if (s.Substring(1,1) == "2") n++;
        if (s.Substring(2,1) == "2") n++;
        if (s.Substring(3,1) == "2") n++;


        Console.WriteLine(n);
    }

    static void DebugWL(object x) { System.Diagnostics.Debug.WriteLine(x); }
    static string[] NextS() { return Console.ReadLine().Trim().Split(' '); }
}