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: Accepted)

#include<iostream>
#include<algorithm>
#include<vector>
#include<stack>
#include <cmath>
#include <limits>
#include<set>
#include <iomanip>
#include <queue>
#pragma GCC optimize("Ofast")
using namespace std;
const long long INF=20000000000;
//setprecision(2) <<

const int MOD = 1000000007;

long long max(long long a,long long b){
	if(a<b)return b;
	else return a;	
}
long long min(long long a,long long b){
	if(a>b)return b;
	else return a;	
}
long long gcd(long long a,long long b){
	if(a<b)swap(a,b);
	if(a%b==0)return b;
	else return gcd(a%b,b);
}

long long lcm(long long a,long long b){
	return a*b/gcd(a,b);
}

long long com(long long n,long long k){
	
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	string s;
	cin>>s;
	int ans=0;
	for(int i=0;i<4;i++){
		if(s[i]=='2')ans++;
	}
	cout<<ans<<endl;
}