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: Wrong Answer)

import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    String[] s = new String[n];
    int start = 0;
    int last = 0;
    int both = 0;
    int cnt = 0;
    for(int i = 0;i < n;i++){
      s[i]=sc.next();
      if(s[i].contains("AB"))cnt++;
      if(s[i].charAt(0)=='B'&&s[i].charAt(s[i].length()-1)=='A')both++;
      else if(s[i].charAt(0)=='B')start++;
      else if(s[i].charAt(s[i].length()-1)=='A')last++;
    }
    boolean amari = false;
    if(both>=1)amari = true;
    while(both>0){
      if(start==last&&start!=0){
        start++;
        both--;
      }else if(start>last&&start>0){
        last++;
        both--;
      }else if(last>start&&last>0){
        start++;
        both--;
      }
    }
    cnt+=Math.min(start,last);
    if(amari&&start==last+1)cnt++;
    System.out.println(cnt);
  }
}