#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long n;
  cin >> n;
  char c[n][n];
  for (long long i = 0; i < n; i++) {
    for (long long j = 0; j < n; j++) {
      cin >> c[i][j];
    }
  }
  bool re = 1, ce = 1;
  for (long long i = 0; i < n; i++) {
    re = 1;
    for (long long j = 0; j < n; j++) {
      if (c[i][j] != 'E') {
        re = 0;
      }
    }
    if (re == 1) {
      break;
    }
  }
  for (long long j = 0; j < n; j++) {
    ce = 1;
    for (long long i = 0; i < n; i++) {
      if (c[i][j] != 'E') {
        ce = 0;
      }
    }
    if (ce == 1) {
      break;
    }
  }
  if (re == 1 && ce == 1) {
    cout << "-1";
    return 0;
  }
  if (re == 1) {
    for (long long j = 0; j < n; j++) {
      for (long long i = 0; i < n; i++) {
        if (c[i][j] != 'E') {
          cout << i + 1 << " " << j + 1 << "\n";
          break;
        }
      }
    }
  } else {
    for (long long i = 0; i < n; i++) {
      for (long long j = 0; j < n; j++) {
        if (c[i][j] != 'E') {
          cout << i + 1 << " " << j + 1 << "\n";
          break;
        }
      }
    }
  }
}
