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;
using static System.Console;

namespace ConsoleApp15
{
    class Class32
    {
        static void Main()
        {
            int N = int.Parse(ReadLine());
            int[] S = new int[3];
            int count = 0;
            for(int i = 0; i < N; i++)
            {
                var r = ReadLine();
                for (int j = 0; j < r.Length - 1; j++)
                    if (r.Substring(j, 2) == "AB") count++;

                if (r.First() == 'B' && r.Last() == 'A')
                    S[0]++;
                else if (r.First() == 'B')
                    S[1]++;
                else if (r.Last() == 'A')
                    S[2]++;
            }
            count += Math.Min(S[1], S[2]);
            int mi = Math.Abs(S[1] - S[2]);
            count += Math.Min(S[0], mi);
            if (S[0] > mi) count += (S[0]-mi) / 2;

            Console.WriteLine(count);
        }
    }
}