C++ Program

Chef decided to find the connections with all of his friends in an unnamed social network. He calls a user of the social network his friend if there is a common substring of the string "chef" and the nickname of that user with length ? 2. Given a list of users of the social network, compute the number of Chef's friends. Input
The first line of the input contains a single integer N denoting the number of users in the social network. N lines follow. Each of these lines contains a single string u denoting the nickname of one user.
Output
Print a single line containing one integer the number of Chef's friends.
Input
4
gennady.korotkevich
kefaa
fhlasek
chemthan
Output
3
Explanations:
1. gennady.korotkevich is a friend to Chef because he has "ch" at the end of his nickname, which is also a substring of "chef" with length 2. 2. the common substring with kefaa is "ef" and the common substring with chemthan is "che"