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;
use std::cmp::min;

fn run() {
    let mut s = String::new();
    std::io::stdin().read_to_string(&mut s).unwrap();
    let mut a = 0;
    let mut b = 0;
    let mut ba = 0;
    let mut ans = 0;
    for s in s.trim().split_whitespace() {
        let t = s.replace("AB", "");
        ans += (s.len() - t.len()) / 2;
        match (t.starts_with("B"), t.ends_with("A")) {
            (true, true)  => ba += 1,
            (true, false) => b += 1,
            (false, true) => a += 1,
            _ => (),
        }
    }
    if ba > 0 {
        ans += ba - 1;
        if a > 0 {
            ans += 1;
            a -= 1;
        }
        if b > 0 {
            ans += 1;
            b -= 1;
        }
    }
    ans += min(a, b);
    println!("{}", ans);
}

fn main() {
    run();
}