Robot Vacuum Cleaner

1000ms

262144K

Description:

Pushok the dog has been chasing Imp for a few hours already.

$\text{[math]}$

Fortunately, Imp knows that Pushok is afraid of a robot vacuum cleaner.

While moving, the robot generates a string t consisting of letters 's' and 'h', that produces a lot of noise. We define noise of string t as the number of occurrences of string "sh" as a subsequence in it, in other words, the number of such pairs (i, j), that i < j and $\text{[math]}$ and $\text{[math]}$ .

The robot is off at the moment. Imp knows that it has a sequence of strings t_i in its memory, and he can arbitrary change their order. When the robot is started, it generates the string t as a concatenation of these strings in the given order. The noise of the resulting string equals the noise of this concatenation.

Help Imp to find the maximum noise he can achieve by changing the order of the strings.

Input:

The first line contains a single integer n (1 ≤ n ≤ 10⁵) — the number of strings in robot's memory.

Next n lines contain the strings t₁, t₂, ..., t_n, one per line. It is guaranteed that the strings are non-empty, contain only English letters 's' and 'h' and their total length does not exceed 10⁵.

Output:

Print a single integer — the maxumum possible noise Imp can achieve by changing the order of the strings.

Sample Input:

4
ssh
hs
s
hhhs

Sample Output:

Sample Input:

2
h
s

Sample Output:

Note:

The optimal concatenation in the first sample is ssshhshhhs.

Informação

Provedor Codeforces

Código CF922D