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 JavaScript (node.js v5.12) (judge verdict: Accepted)

function main(arg) {
	arg = arg.split("\n")[0]

	var src = arg.split("")
	var count = 0
	for (var i  = 0; i < src.length; i++) {
		if (src[i] == "2") {
			count++
		}
	}
	console.log(count)
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));