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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		char[] n = sc.next().toCharArray();
		int ans = 0;
		for (int i = 0; i < n.length; i++) {
			if (n[i] == '2') {
				ans++;
			}
		}
		System.out.println(ans);
	}
}