#include <bits/stdc++.h>
using namespace std;
int N;
char field[110][110];
bool check_solution(bool do_print, bool swapped) {
  for (int r = 0; r < N; ++r) {
    int c;
    for (c = 0; c < N; ++c) {
      if (field[r][c] == '.') break;
    }
    if (c == N) return false;
    if (do_print) {
      if (swapped)
        printf("%d %d\n", c + 1, r + 1);
      else
        printf("%d %d\n", r + 1, c + 1);
    }
  }
  return true;
}
int main(void) {
  scanf("%d", &N);
  for (int r = 0; r < N; ++r) scanf("%s", field[r]);
  if (check_solution(false, false)) {
    check_solution(true, false);
  } else {
    for (int r = 0; r < N; ++r) {
      for (int c = r + 1; c < N; ++c) {
        swap(field[r][c], field[c][r]);
      }
    }
    if (check_solution(false, true))
      check_solution(true, true);
    else
      puts("-1");
  }
  return 0;
}
