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;

public class Solution
{
    public static void Main()
    {
        var n = int.Parse(Console.ReadLine());
        int count = 0;
        int ba = 0;
        int xa = 0;
        int bx = 0;
        for (int i = 0; i < n; i++)
        {
            var s = Console.ReadLine();
            count += s.Replace("AB", "_").Count(c => c == '_');
            if (s.First() == 'B' && s.Last() == 'A')
            {
                ba++;
            }
            else if (s.Last() == 'A')
            {
                xa++;
            }
            else if (s.First() == 'B')
            {
                bx++;
            }
        }

        var max = count;
        if (xa > 0)
        {
            xa--;
        }
        else if (ba > 0)
        {
            ba--;
        }
        else
        {
            Console.WriteLine(max);
            return;
        }

        max += ba;
        ba = 0;
        if (bx > 0)
        {
            max++;
            bx--;
        }
        else
        {
            Console.WriteLine(max);
            return;
        }

        max += Math.Min(xa, bx);
        Console.WriteLine(max);
    }
}