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++14 (GCC 5.4.1) (judge verdict: Runtime Error)

#include <bits/stdc++.h>
using namespace std;

int main() {
  vector<char> data(4);
  for (int i = 0; i < 5; i++) {
    cin >> data.at(i);
  }

  // 答えを保持する変数
  int answer = 0;

  for (int i = 0; i < 5; i++) {

    if (data.at(i) == '2') {
      answer++;
    }

  }

  cout << answer << endl;
}