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

int main(int argc, char const* argv[])
{
	int counter=0;
	int b,ans;
	string N;
	cin>>N;
	// int l=std::strlen(N);
	int l=N.length();
	for (int j = 0; j < l; j++) {
		if(N[j]=='0') counter+=1;
	}

	if(counter>8){
		ans=counter-8;
	}
	else if(counter<8){
		ans=8-counter;
	}
	else{
		ans=0;
	}
	cout<<ans<<endl;
	return 0;
}