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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
)

var sc = bufio.NewScanner(os.Stdin)

const inf = 1 << 60

func ri() (n int) {
	sc.Scan()
	for _, v := range sc.Bytes() {
		n = n*10 + int(v-48)
	}
	return
}

func rs() string {
	sc.Scan()
	return sc.Text()
}

func smaller(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func main() {
	sc.Split(bufio.ScanWords)
	n := ri()

	var s string
	ctAB, ctTailA, ctHeadB, ctTailAHeadB := 0, 0, 0, 0
	for i := 0; i < n; i++ {
		s = rs()
		for j := 0; j < len(s)-1; j++ {
			if s[j] == 'A' && s[j+1] == 'B' {
				ctAB++
			}
		}
		if s[len(s)-1] == 'A' {
			ctTailA++
		}
		if s[0] == 'B' {
			ctHeadB++
		}
		if s[len(s)-1] == 'A' && s[0] == 'B' {
			ctTailAHeadB++
		}
	}

	ans := -1
	ans = ctAB + smaller(ctTailA, ctHeadB)
	if ctTailAHeadB != 0 && ctTailAHeadB == ctTailA && ctTailAHeadB == ctHeadB {
		ans--
	}
	fmt.Println(ans)
}