#include <bits/stdc++.h>
using namespace std;
int main(int argc, char const *argv[]) {
  int n;
  char s[105][105];
  while (~scanf("%d", &n)) {
    for (int i = 1; i <= n; ++i) scanf("%s", s[i] + 1);
    vector<pair<int, int> > r;
    bool rc = true;
    for (int i = 1; i <= n; ++i) {
      int j;
      for (j = 1; j <= n; ++j)
        if (s[i][j] == '.') {
          r.push_back(pair<int, int>(i, j));
          break;
        }
      if (j > n) {
        rc = false;
        break;
      }
    }
    vector<pair<int, int> > c;
    bool cc = true;
    for (int j = 1; j <= n; ++j) {
      int i;
      for (i = 1; i <= n; ++i)
        if (s[i][j] == '.') {
          c.push_back(pair<int, int>(i, j));
          break;
        }
      if (i > n) {
        cc = false;
        break;
      }
    }
    if (rc) {
      for (int i = 0; i < n; ++i) printf("%d %d\n", r[i].first, r[i].second);
    } else if (cc) {
      for (int i = 0; i < n; ++i) printf("%d %d\n", c[i].first, c[i].second);
    } else {
      puts("-1");
    }
  }
  return 0;
}
