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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

fun main(args: Array<String>) {
    val N = readLine()!!.toInt()
    val s = Array(N) { readLine()!! }

    val a = s.indices.filter { s[it].last() == 'A' }
    val b = s.indices.filter { s[it].first() == 'B' }
    val ab = s.indices.filter { s[it].first() == 'B' && s[it].last() == 'A' }

    var r = s.map {
        var t = 0
        for (i in 0 .. it.length - 2) {
            if (it.substring(i, i + 2) == "AB") {
                t++
            }
        }
        t
    }.sum()

    if (ab.size == a.size && ab.size == b.size) {
        r += ab.size - 1
    } else {
        r += Math.min(a.size, b.size)
    }

    println(r)
}