#include <bits/stdc++.h>
using namespace std;
vector<string> a;
long long i, j, k, sumA = 0, sumB = 0, min_sumA = 8, min_sumB = 8;
string t;
int main() {
  for (i = 0; i < 8; i++) {
    cin >> t;
    a.push_back(t);
  }
  for (i = 0; i < 8; i++)
    for (j = 0; j < 8; j++) {
      sumA = sumB = 0;
      if (a[i][j] == 'W') {
        for (k = i - 1; k >= 0; k--)
          if (a[k][j] != 'B')
            ++sumA;
          else {
            sumA = min_sumA;
            break;
          }
        sumB = min_sumB;
      } else if (a[i][j] == 'B') {
        for (k = i + 1; k < 8; k++)
          if (a[k][j] != 'W')
            ++sumB;
          else {
            sumB = min_sumB;
            break;
          }
        sumA = min_sumA;
      } else {
        sumA = min_sumA;
        sumB = min_sumB;
      }
      if (sumA < min_sumA) min_sumA = sumA;
      if (sumB < min_sumB) min_sumB = sumB;
    }
  if (min_sumA <= min_sumB)
    printf("A");
  else
    printf("B");
  return 0;
}
