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)

import sys
input = sys.stdin.readline


def main():
    N = int(input())
    ba = []
    ca = []
    bc = []
    cc = []
    for _ in range(N):
        s = input().strip()
        b = (s[0] == "B")
        a = (s[-1] == "A")
        if b and a:
            ba.append(s)
        elif not b and a:
            ca.append(s)
        elif b and not a:
            bc.append(s)
        else:
            cc.append(s)
    S = ""
    while ba or ca or bc:
        if ca:
            S += ca.pop()
        if ba:
            S += ba.pop()
        if bc:
            S += bc.pop()
    for s in cc:
        S += s
    print(S.count("AB"))


if __name__ == '__main__':
    main()