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 re
N = int(input())
s=[input() for _ in range(N)]

counter = 0
for n in range(N):
    counter += len(re.findall('AB', s[n]))
lb_ra = 0
lb = 0
ra = 0
frag = False
if N>1:

    for n in range(N):
        l, r = s[n][0]=='B', s[n][-1]=='A'
        if l and r:
            lb_ra += 1
        elif l:
            lb += 1
        elif r:
            ra +=1

    if ra>lb_ra:
        counter+=lb_ra
        ra = ra
        lb_ra = 0
        frag=True
    else:
        counter+=ra
        ra = ra
        lb_ra = lb_ra-ra
        frag=True
    
    if lb>lb_ra:
        counter+=lb_ra
        lb = lb
        lb_ra=0
        frag=True
    else:
        counter+=lb
        lb = lb
        lb_ra=lb_ra-lb
        frag=True
    counter+= min(lb,ra)
    
    if frag:
        counter+=lb_ra
        
print(counter)