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.Linq;

namespace diverta2019ProgrammingContest
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = int.Parse(Console.ReadLine());
            long numai = 0;
            long beginb = 0;
            long enda = 0;
            long both = 0;
            for (int i = 0; i < N; ++i)
            {
                var si = Console.ReadLine();
                var ai = CountOf(si);
                numai += ai;
                var begin = si[0];
                var end = si[si.Length - 1];
                if ('B' == begin & 'A' == end)
                { ++both; }
                else if ('B' == begin)
                { ++beginb; }
                else if ('A' == end)
                { ++enda; }
            }
            var hosei = 0;
            if (0 != both)
            {
                --both;
                if (0 != enda) { --enda; ++hosei; }
                if (0 != beginb) { --beginb; ++hosei; }
            }
            var cnt = numai + hosei + both + Math.Min(beginb, enda);
            Console.WriteLine($"{cnt}");
        }

        public static int CountOf(string target)
        {
            int count = 0;
            string str = "AB";
            int index = target.IndexOf(str, 0);
            while (index != -1)
            {
                count++;
                index = target.IndexOf(str, index + str.Length);
            }
            return count;
        }
    }
}