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;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = int.Parse(Console.ReadLine());
            var sList = new List<string>();
            var a = 0;
            var b = 0;
            var ab = 0;
            var sum = 0;
            for (int i = 0; i < N; i++)
            {
                var s = Console.ReadLine();
                if (s[s.Length - 1] == 'A') a++;
                if (s[0] == 'B') b++;
                if (s[s.Length - 1] == 'A' && s[0] == 'B') ab++;
                sum += CountOf(s, "AB");
            }

            if (b == ab)
                Console.WriteLine(sum + Math.Min(a, b) - 1);
            else
                Console.WriteLine(sum + Math.Min(a, b));
        }

        public static int CountOf(string target, string str)
        {
            int count = 0;

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

            return count;
        }
    }
}