Language: C++

/*Function Template*/
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
const int MAX = 510000;
const int MOD = 1000000007;
#define rep(i, n) for(ll i = 0; i < (n); i++)
#define Rep(i, n) for(ll i = 1; i < (n); i++)
#define ALL(a)  (a).begin(),(a).end()
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll fac[MAX], finv[MAX], inv[MAX];


template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (ll i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }

}
ll Len(ll n) {
  ll s=0;
  while(n!=0) s++, n/=10;
  return s;
}


ll Sint(ll n) {
  ll m=0,s=0,a=n;
  while(a!=0) s++, a/=10;
  for(ll i=s-1;i>=0;i--) m+=n/((ll)pow(10,i))-(n/((ll)pow(10,i+1)))*10;
  return m;
}


ll Svec(vector<ll> v){
  ll n=0;
  for(ll i=0;i<v.size();i++) n+=v[i];
  return n;
}


ll GCD(ll a,ll b) {
  return b ? GCD(b,a%b) : a;
}


ll LCM(ll a,ll b){
  return a/GCD(a,b)*b;
}


ll Factorial(ll n){
  ll m=1;
  while(n>=1) m*=n,n--;
  return m;
}

void runlength(string s,vector<pair<char,ll>> &p){
  ll x=1;
  if(s.size()==1){
    p.push_back(pair<char,ll>(s[0],1));
  }
  for(ll i=0;i<s.size()-1;i++){
    if(s[i]==s[i+1]){
      x++;
      if(i==s.size()-2){
        p.push_back(pair<char,ll>(s[i],x));
      }
    }else{
      p.push_back(pair<char,ll>(s[i],x));
      x=1;
      if(i==s.size()-2){
        p.push_back(pair<char,ll>(s[s.size()-1],x));
      }
    }
  }
}




ll COM(ll n,ll k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

const int MAX_N=100010;
vector<bool> sieve_of_eratosthenes(){
  vector<bool> isPrime(MAX_N+1,true);
  for(int i=2;i<=MAX_N;i++){
    if(isPrime[i]){
      for(int j=2*i;j<=MAX_N;j+=i){
        isPrime[j]=false;
      }
    }
  }
  return isPrime;
}



/*↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓*/
int main() {
  IOS;
  ll n,ans=0,A=0,B=0;
  bool BA=false;
  cin>>n;
  vector<string> v(n);
  rep(i,n) cin>>v[i];
  rep(i,n){
    if(v[i][0]=='B') B++;
    if(v[i][v[i].size()-1]=='A') A++;
    if(v[i][0]=='B' && v[i][v[i].size()-1]=='A') BA=true;
    ans+=count(ALL(v[i]),"AB");
  }
  if(A==B && BA){
    cout<<ans+A-1<<endl;
  }else{
    cout<<ans+min(A,B)<<endl;
  }
  
}

Compiler output:
In file included from /usr/include/c++/14/bits/stl_algobase.h:71,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:2:
/usr/include/c++/14/bits/predefined_ops.h: In instantiation of 'bool __gnu_cxx::__ops::_Iter_equals_val<_Value>::operator()(_Iterator) [with _Iterator = __gnu_cxx::__normal_iterator<char*, std::__cxx11::basic_string<char> >; _Value = const char [3]]':
/usr/include/c++/14/bits/stl_algobase.h:2163:12:   required from 'typename std::iterator_traits< <template-parameter-1-1> >::difference_type std::__count_if(_InputIterator, _InputIterator, _Predicate) [with _InputIterator = __gnu_cxx::__normal_iterator<char*, __cxx11::basic_string<char> >; _Predicate = __gnu_cxx::__ops::_Iter_equals_val<const char [3]>; typename iterator_traits< <template-parameter-1-1> >::difference_type = long int]'
 2163 |         if (__pred(__first))
      |             ~~~~~~^~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4033:29:   required from 'typename std::iterator_traits< <template-parameter-1-1> >::difference_type std::count(_IIter, _IIter, const _Tp&) [with _IIter = __gnu_cxx::__normal_iterator<char*, __cxx11::basic_string<char> >; _Tp = char [3]; typename iterator_traits< <template-parameter-1-1> >::difference_type = long int]'
 4033 |       return std::__count_if(__first, __last,
      |              ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
 4034 |                              __gnu_cxx::__ops::__iter_equals_val(__value));
      |                              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:135:15:   required from here
  135 |     ans+=count(ALL(v[i]),"AB");
      |          ~~~~~^~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/predefined_ops.h:270:24: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
  270 |         { return *__it == _M_value; }
      |                  ~~~~~~^~~~~~~~~~~