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)

N = int(input())
S_tail_a_head_b = []
S_tail_a = []
S_head_b = []
S_ab = []
for _ in range(N):
    s = input()
    if s.find('AB') == -1 and s[0] != 'B' and s[-1] != 'A':
        continue
    elif s[0] == 'B' and s[-1] == 'A':
        S_tail_a_head_b.append(s)
    elif s[0] == 'B':
        S_head_b.append(s)
    elif s[-1] == 'A':
        S_tail_a.append(s)
    else:
        S_ab.append(s)

S = ''.join(S_ab)
head_b = ''
for i in range(max(len(S_head_b), len(S_tail_a))):
    if len(S_head_b) > i and len(S_tail_a) > i:
        S += S_tail_a[i] + S_head_b[i]
    elif len(S_head_b) <= i:
        S += ''.join(S_tail_a[i:])
        break
    else:
        head_b = ''.join(S_head_b[i:])
        break

S += ''.join(S_tail_a_head_b) + head_b

print(S.count('AB'))