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# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;

class Diverta_2019_C
{
    static void Main(string[] args)
    {
        int N = int.Parse(Console.ReadLine());

        int count = 0;

        int A = 0;
        int B = 0;
        int AB = 0;

        string[] s = new string[N];
        for (int i = 0; i < N; i++)
        {
            s[i] = Console.ReadLine();
            for (int j = 0; j < s[i].Length; j++)
            {
                int pos = s[i].IndexOf("AB", j);
                if (pos < 0) break;

                count++;
                j += pos;
            }

            if (s[i][0] == 'B' && s[i][s[i].Length-1] =='A') AB++;
            else if(s[i][0] == 'B') B++;
            else if(s[i][s[i].Length-1] == 'A') A++;
        }

        if(A==B) count += Math.Min(A, B) + AB -1;
        else count += Math.Min(A, B) + AB;

        Console.WriteLine(count);
    }
}