#include <bits/stdc++.h>
using namespace std;
int main() {
  vector<int64_t> A(8, 8);
  vector<int64_t> A_high(8, 0);
  vector<int64_t> B(8, 8);
  vector<int64_t> B_high(8, 8);
  int64_t amax = 8;
  int64_t bmax = 8;
  char k;
  for (int64_t i = 0; i < 8; i++) {
    for (int64_t j = 0; j < 8; j++) {
      cin >> k;
      if (k == 'B') {
        if (B_high[j] > i) {
          B_high[j] = i;
        }
        B[j] = 7 - i;
      } else if (k == 'W') {
        A_high[j] = i;
        if (A[j] > i) {
          A[j] = i;
        }
      }
    }
  }
  for (int64_t i = 0; i < 8; i++) {
    if (amax > A[i] && (B_high[i] > A[i])) {
      amax = A[i];
    }
    if (bmax > B[i] && (A_high[i] < 7 - B[i])) {
      bmax = B[i];
    }
  }
  if (amax <= bmax) {
    cout << 'A' << endl;
  } else {
    cout << 'B' << endl;
  }
  return 0;
}
