Problem:
Score : 400 points

Problem Statement

Snuke has N strings. The i-th string is s_i.

Let us concatenate these strings into one string after arranging them in some order.
Find the maximum possible number of occurrences of AB in the resulting string.

Constraints

1 \leq N \leq 10^{4}

2 \leq |s_i| \leq 10

s_i consists of uppercase English letters.

Input

Input is given from Standard Input in the following format:

N
s_1
\vdots
s_N

Output

Print the answer.

Sample Input 1

3
ABCA
XBAZ
BAD

Sample Output 1

2

For example, if we concatenate ABCA, BAD and XBAZ in this order, the resulting string ABCABADXBAZ has two occurrences of AB.

Sample Input 2

9
BEWPVCRWH
ZZNQYIJX
BAVREA
PA
HJMYITEOX
BCJHMRMNK
BP
QVFABZ
PRGKSPUNA

Sample Output 2

4

Sample Input 3

7
RABYBBE
JOZ
BMHQUVA
BPA
ISU
MCMABAOBHZ
SZMEHMA

Sample Output 3

4

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

# -*- coding: utf-8 -*-

def solve():
    NAB, NBA, NB_, N_A = 0, 0, 0, 0
    for _ in range(int(input())):
        S = input()
        NAB += S.replace('AB', '-').count('-')
        b, a = S.startswith('B'), S.endswith('A')
        NBA += b&a
        NB_ += b&(~a)
        N_A += (~b)&a
    res = NAB + max(NBA-1, 0) + (NB_>=1) + (N_A>=1) + max(min(NB_, N_A)-1, 0)

    return str(res)

if __name__ == '__main__':
    print(solve())