#include<bits/stdc++.h>
using namespace std;
int cnt;
int main() {
	string b;
	cin>>b;
	for(int i=1;i<=b.size();i++){
		if(b[i]=='2')cnt++;
		else if(b[i]=='6')cnt++;
		else if(b[i]=='8')cnt+=2;
		else if(b[i]=='9')cnt++;
		else if(b[i]=='0')cnt++; 
	}
	cout<<cnt;
}

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