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)

#!/usr/bin/env python3
n = int(input())
s = [input() for _ in range(n)]
ans = 0
xa = 0
bx = 0
bxa = 0
for c in s:
    ans += sum(c[i:i + 2] == 'AB' for i in range(len(c) - 1))
    if c[0] == 'B':
        bx += 1
    if c[-1] == 'A':
        xa += 1
    if c[0] == 'B' and c[-1] == 'A':
        bxa += 1
xa -= bxa
bx -= bxa
ans += min(xa, bxa)
xa = max(0, xa - bxa)
ans += min(bxa, bx)
bx = max(0, bx - bxa)
ans += min(xa, bx)
ans += max(0, bxa - 1)
print(ans)