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: Accepted)

#include <iostream>
#include <vector>
#include <string>

int main() {
  int N;
  std::cin >> N;
  std::vector<std::string> S(N);
  for(auto &s:S)
    std::cin >> s;
  int start_b = 0;
  int end_a = 0;
  int start_b_end_a = 0;
  int include_ab = 0;
  for(auto &s:S){
    std::string ss = s;
    while(true) {
      int pos=ss.find("AB");
      if(pos==std::string::npos)break;
      ss = ss.substr(pos+2,ss.size()-pos-2);
      include_ab++;
    }
    if(s[0]=='B' && s[s.size()-1]=='A')
      start_b_end_a++;
    else if(s[0]=='B')
      start_b++;
    else if(s[s.size()-1]=='A')
      end_a++;

  }
  int ans = include_ab;
  if(start_b_end_a >0 && start_b == 0 && end_a == 0)
    ans += start_b_end_a - 1;
  else
    ans += start_b_end_a + std::min(start_b, end_a);
  std::cout << ans << std::endl;
  return 0;
}

/*
9
BEWPVCRWH
ZZNQYIJX
BAVREA
PA
HJMYITEOX
BCJHMRMNK
BP
QVFABZ
PRGKSPUNA
4
*/