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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Diverta2019_C
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());

            int abCount = 0;
            bool falseFindFlag = false;
            int firstCount = 0;
            int lastCount = 0;

            for (int i = 0; i < n; ++i)
            {
                string str = Console.ReadLine();
                abCount += CountOf(str, "AB");

                bool firstFlag = (str[0] == 'B');
                bool lastFlag = (str[str.Length-1] == 'A');

                if (lastFlag) { ++lastCount; }
                if (firstFlag) { ++firstCount; }
                if (!falseFindFlag && ((lastFlag && !firstFlag) || (!lastFlag && firstFlag))) { falseFindFlag = true; }
            }

            int addCount = (firstCount < lastCount) ? firstCount : lastCount;
            abCount += addCount;
            if (!falseFindFlag && addCount != 0) { --abCount; }

            Console.WriteLine("{0}", abCount);
        }

        public static int CountOf(string target, params string[] strArray)
        {
            int count = 0;

            foreach (string str in strArray)
            {
                int index = target.IndexOf(str, 0);
                while (index != -1)
                {
                    count++;
                    index = target.IndexOf(str, index + str.Length);
                }
            }

            return count;
        }
    }
}