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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
#define endl '\n';
#define FASTER ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
const ll POSITIVE_INFINITY = 9223372036854775807;
const ll NEGATIVE_INFINITY = -9223372036854775807;
const ll MOD = 1000000007;
const ld PI = acos(-1.0);

template <typename T> inline T bigMod(T A,T B,T M = MOD){A %= M;T ret = 1;while(B){if(B & 1) ret = (ret * A) % M;A = (A * A) % M;B = B >> 1;}return ret;}
template <typename T> inline T invMod (T A,T M = MOD){return bigMod(A,M-2,M);}

const int N = 10005;

int main(){
  FASTER;
  int n;
  cin >> n;
  ll ans = 0;
  ll a = 0;
  ll b = 0;
  ll c = 0;
  for (int i = 0; i < n; i++){
    string ar;
    cin >> ar;
    for (int i = 0; i + 1 < ar.size(); i++){
      if (ar[i] == 'A' && ar[i + 1] == 'B'){
        ans++;
      }
    }
    if (ar[ar.size() - 1] == 'A' && ar[0] == 'B'){
      c++;
    }
    if (ar[ar.size() - 1] == 'A'){
      a++;
    }
    if (ar[0] == 'B'){
      b++;
    }
  }
  cout << (ans + min(a, b) - c) << '\n';
  return 0;
}