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 std::cin;
using std::cout;
using std::cerr;

using std::vector;
using std::map;
using std::array;
using std::set;
using std::string;

using std::pair;
using std::make_pair;

using std::tuple;
using std::make_tuple;
using std::get;

using std::min;
using std::abs;
using std::max;
using std::swap;

using std::unique;
using std::sort;
using std::generate;
using std::reverse;
using std::min_element;
using std::max_element;

#ifdef LOCAL
#define LASSERT(X) assert(X)
#else
#define LASSERT(X) {}
#endif

template <typename T>
T input() {
    T res;
    cin >> res;
    LASSERT(cin);
    return res;
}

template <typename IT>
void input_seq(IT b, IT e) {
    std::generate(b, e, input<typename std::remove_reference<decltype(*b)>::type>);
}

#define SZ(vec)         int((vec).size())
#define ALL(data)       data.begin(),data.end()
#define RALL(data)      data.rbegin(),data.rend()
#define TYPEMAX(type)   std::numeric_limits<type>::max()
#define TYPEMIN(type)   std::numeric_limits<type>::min()

int main() {
    std::iostream::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    // code here
    int n = input<int>();
    vector<string> s(n);
    input_seq(ALL(s));

    int ans = 0;
    vector<int> en_a, st_b;

    int i = -1;
    for (string& str: s) {
        ++i;
        
        if (str.back() == 'A')
            en_a.push_back(i);
        if (str[0] == 'B')
            st_b.push_back(i);

        for (int i = 1; i < SZ(str); ++i)
            if (str[i - 1] == 'A' and str[i] == 'B')
                ++ans;
    }

    if (en_a == st_b and st_b.size() == 1) {
        en_a.clear();
        st_b.clear();
    }

    ans += min(SZ(en_a), SZ(st_b));
    cout << ans << "\n";
    
    return 0;
}