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 int countAB(String str) {
		int cnt = 0;
		int start = 0;
		while(true) {
			int ix = str.indexOf("AB", start);
			if (ix < 0) {
				return cnt;
			}
			cnt++;
			start = ix + 1;
		}
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		int incAB = 0;
		int endA = 0;
		int startB = 0;
		int bothAB = 0;
		for (int i = 0; i < N; i++) {
			String s = sc.next();
			incAB += countAB(s);
			if (s.charAt(0) == 'B') {
				if (s.charAt(s.length() - 1) == 'A') {
					bothAB++;
				} else {
					startB++;
				}
			} else if (s.charAt(s.length() - 1) == 'A') {
				endA++;
			}
		}
		// System.out.println("incAB  = " + incAB);
		// System.out.println("endA   = " + endA);
		// System.out.println("startB = " + startB);
		// System.out.println("bothAB = " + bothAB);


		int ans = incAB;
		int plus;
		if (endA == 0) {
			if (startB == 0) {
				plus = Math.max(bothAB - 1, 0);
			} else {
				// startBのみ
				plus = bothAB;
			}
		} else {
			if (startB == 0) {
				plus = bothAB;
			} else {
				plus = bothAB + Math.min(endA, startB);
			}
		}
		System.out.println(incAB + plus);

		// System.out.println(Math.max(x, y));
	}
}