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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
 
using namespace std;
 
int main() {
  int n;
  cin >> n;
  int ans = 0;
  int first_b = 0;
  int last_a = 0;
  int both_a_b = 0;
 
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    int pos = s.find("AB");
    while (pos != std::string::npos) {
      ans++;
      pos = s.find("AB", pos + 1);
    }
    if (s.front() == 'B') first_b++;
    if (s.back() == 'A') last_a++;
    if (s.front() == 'B' && s.back() == 'A') both_a_b++;
  }
  ans += min(first_b, last_a);
  if (min(first_b, last_a) == n) ans -= 1;
  else if (first_b == 1 && last_a == 1 && both_a_b == 1) ans -= 1;
  cout << ans << endl;
  return 0;
}