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 (1.42.0) (judge verdict: Accepted)

use std::io::*;
use std::str::FromStr;
use std::cmp::min;

fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("faild to read char") as char)
        .take_while(|c| !c.is_whitespace())
        .collect();
    token
        .parse()
        .ok()
        .expect("faild to parse token")
}

fn main(){
    let n: u64 = read();
    let s: Vec<Vec<char>> = (0..n).map(|_| read::<String>().chars().collect()).collect();

    let mut start_b: u64 = 0;
    let mut end_a: u64 = 0;
    let mut both: u64 = 0;
    let mut ret: u64 = 0;

    for c in &s {
        if c[0] == 'B' && c[c.len() -1] == 'A' {
            both += 1;
        } else if c[c.len() - 1] == 'A' {
            end_a += 1;
        } else if c[0] == 'B' {
            start_b += 1;
        }

        for i in 1..(c.len()) {
            if c[i - 1] == 'A' && c[i] == 'B' {
                ret += 1;
            }
        }
    }

    if both == 0 {
        ret += min(start_b, end_a);
    } else if start_b == 0 && end_a == 0 {
        ret += both - 1;
    } else {
        ret += both + min(end_a, start_b);
    }
    println!("{}", ret);
}