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: Wrong Answer)

package main

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

var r = bufio.NewReader(os.Stdin)
var w = bufio.NewWriter(os.Stdout)

func main() {
	defer w.Flush()

	var n int
	fmt.Fscanf(r, "%d\n", &n)

	s := make([]string, n)
	for i := 0; i < n; i++ {
		fmt.Fscanf(r, "%s\n", &s[i])
	}

	lastA := 0
	firstB := 0
	lastAAndFirstB := 0
	count := 0
	for i, _ := range s {
		count += strings.Count(s[i], "AB")
		if strings.HasSuffix(s[i], "A") && strings.HasPrefix(s[i], "B") {
			lastAAndFirstB++
			continue
		}
		if strings.HasSuffix(s[i], "A") {
			lastA++
			continue
		}
		if strings.HasPrefix(s[i], "B") {
			firstB++
			continue
		}
	}
	if lastA < firstB {
		count += lastA
		firstB -= lastA
		if firstB < lastAAndFirstB {
			count += firstB
		} else {
			count += lastAAndFirstB
		}
	} else {
		count += firstB
		lastA -= firstB
		if lastA < lastAAndFirstB {
			count += lastA
		} else {
			count += lastAAndFirstB
		}
	}

	fmt.Fprintln(w, count)
}