Mahabali Bheem and The Chef

Mahabali Bheem is visiting his best friend Chef. They are discussing their strategy for the war. Self-obsessed Chef suggests that a person is their ally if there is a common substring of the string "chef" and the name of that person, with length ≥ 2. Given a list of people, compute the number of allies. ### Input - First line of input contains a single integer $N$, denoting the number of people.