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;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
public class ABC
{
    public static void Main()
    {
        int N = int.Parse(Console.ReadLine());
        Queue<String> B_start = new Queue<String>();
        Queue<String> A_end = new Queue<String>();
        string both = "";
        string s = "";
        for (int i = 0; i < N; i++)
        {
            string temp = Console.ReadLine();
            if (temp.EndsWith("A") && temp.StartsWith("B"))
            {
                both += temp;
            }
            else if (temp.EndsWith("A"))
            {
                A_end.Enqueue(temp);
            }
            else if (temp.StartsWith("B"))
            {
                B_start.Enqueue(temp);
            }
            else
            {
                s += temp;
            }



        }
        if (A_end.Count > 0) both = A_end.Dequeue() + both;
        if (B_start.Count > 0) both = both + B_start.Dequeue();
        while (A_end.Count != 0 && B_start.Count != 0)
        {
            both = both + A_end.Dequeue() + B_start.Dequeue();
        }
        s = s + both;
        int moto_length = s.Length;
        s = s.Replace("AB", "");
        int result = -s.Length + moto_length;
        Console.WriteLine(result / 2);

    }
}