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 Rust (1.15.1) (judge verdict: Accepted)

use std::io::Read;

fn main() {
    let mut buf = String::new();
    std::io::stdin().read_to_string(&mut buf).ok();
    let mut it = buf.split_whitespace();
    let n = it.next().unwrap().parse::<usize>().unwrap();
    let s = (0..n).map(|_| it.next().unwrap()).collect::<Vec<_>>();
    let mut res = 0;
    let mut cnt_a = 0;
    let mut cnt_b = 0;
    let mut check_ab = false;
    for &c in &s {
        res += c.matches("AB").count();
        let start_b = c.starts_with("B");
        let end_a = c.ends_with("A");
        if start_b && end_a {
            if check_ab {
                res += 1;
            } else {
                check_ab = true;
            }
        } else if start_b {
            cnt_b += 1;
        } else if end_a {
            cnt_a += 1;
        }
    }
    if check_ab {
        if cnt_a > 0 {
            res += 1;
            cnt_a -= 1;
        }
        if cnt_b > 0 {
            res += 1;
            cnt_b -= 1;
        }
    }
    res += std::cmp::min(cnt_a, cnt_b);
    println!("{}", res);
}