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 (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
int main()
{
  int num;
  int cnt;
  int d;
  int two;
  int i;
  int val;
  
  cnt = scanf("%d", &num);

  val = 1;
  for (i=0; i<4; i++) {
    d = (num % (val*10)) / val;
    val *= 10;
    if (d == 2) two++;
  }

  printf("%d", two);
  
  return 0;
}