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

using namespace std;

int main(int argc, char* argv[]) {
  int N;
  cin >> N;

  vector<string> s(N);
  for (int i = 0; i < N; ++i)
    cin >> s[i];

  long long ret = 0;
  long long start_with_b = 0;
  long long end_with_a = 0;
  for (int i = 0; i < N; ++i) {
    if (s[i].front() == 'B')
      ++start_with_b;
    if (s[i].back() == 'A')
      ++end_with_a;
    for (int j = 0; j < s[i].size() - 1; ++j) {
      if (s[i].substr(j, 2) == "AB")
        ++ret;
    }
  }

  ret += min(start_with_b, end_with_a);

  cout << ret << endl;

  return 0;
}