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 n;
    int a[4];
    scanf("%d",&n);
    a[0] = n%10;
    a[1] = n/10%10;
    a[2] = n/100%10;
    a[3] = n/1000%10;
    int c;
    c = 0;
    for(int i = 0;i<4;i++){
        if(a[i] == 2){
            c++;
        }
    }
    printf("%d\n",c);
    return 0;
}