#include <bits/stdc++.h>
using namespace std;
vector<string> grid;
int main() {
  int n;
  cin >> n;
  string line = "";
  for (int i = 0; i < n; i++) {
    cin >> line;
    grid.push_back(line);
  }
  bool rowblock = false;
  bool colblock = false;
  for (int i = 0; i < n; i++) {
    bool found = false;
    for (int j = 0; j < n; j++) {
      if (grid[i][j] == '.') {
        found = true;
      }
    }
    if (!found) {
      rowblock = true;
    }
  }
  for (int j = 0; j < n; j++) {
    bool found = false;
    for (int i = 0; i < n; i++) {
      if (grid[i][j] == '.') {
        found = true;
      }
    }
    if (!found) {
      colblock = true;
    }
  }
  if (rowblock && colblock) {
    cout << -1 << endl;
    return 0;
  }
  if (rowblock == false) {
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < n; j++) {
        if (grid[i][j] == '.') {
          cout << i + 1 << " " << j + 1 << endl;
          break;
        }
      }
    }
  } else {
    for (int j = 0; j < n; j++) {
      for (int i = 0; i < n; i++) {
        if (grid[i][j] == '.') {
          cout << i + 1 << " " << j + 1 << endl;
          break;
        }
      }
    }
  }
  return 0;
}
