#include <bits/stdc++.h>
using namespace std;
int main(){
	int n,sum=0;
	cin>>n;
	string s1="codeforce";
	for(int i=0;i<n;i++){
		string s2;
		cin>>s2;
		for(int i=0;i<s1.length();i++){
			for(int i=0;i<s2.length();i++){
				if(s1[i]!=s2[i]){
					sum++;
				}
			}
		} 
	}
	cout<<sum;
	return 0;
}

https://codeforces.com/contest/1829/problem/A