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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;

public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int headB = 0;
        int tailA = 0;
        int headBandtailA = 0;
        int ABcount = 0;
        String[] S = new String[N];

        for (int i = 0; i < N; i++) {
            S[i] = sc.next();
        }

        for (int i = 0; i < N; i++) {
            String s = S[i];
            if (s.startsWith("B")) {
                if (s.endsWith("A")) {
                    headBandtailA++;
                } else {
                    headB++;
                }
            } else if (s.endsWith("A")) {
                tailA++;
            }

            int index = 0;
            while (index != -1) {
                index = s.indexOf("AB");
                if (index != -1) {
                    ABcount++;
                    if(s.length() >= index+2){
                        s = s.substring(index+2);
                    } else {
                        index = -1;
                    }
                }
            }
        }

        if (headB == 0 && tailA == 0) {
            if(headBandtailA > 0){
                System.out.println(ABcount + headBandtailA -1);
            } else {
                System.out.println(ABcount);
            }

        } else {
            System.out.println(ABcount + headBandtailA + Math.min(headB,tailA));
        }
    }
}