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(input){
  var ans = 0;
  for (var i=0; i<input[0].length; i++){
    if (input[0][i] === '2') 
      ans ++;
  }

  console.log(ans);
}


function parse(line){
  var ret = [];
  var arr = line.split(' ');
  for (var i = 0; i < arr.length; i++) {
    ret.push(parseInt(arr[i]));
  }
  return ret;
}

var input = '';

process.stdin.resume();
process.stdin.setEncoding('utf8');
process.stdin.on('data', function(chunk) {
  input += chunk;
});
process.stdin.on('end', function() {
  input = input.split('\n');
  main(input);
});