#include <bits/stdc++.h>
using namespace std;
char ch[200][200];
int rp[200], cp[200];
int main() {
  int n;
  while (cin >> n) {
    memset(rp, 0, sizeof(rp));
    memset(cp, 0, sizeof(cp));
    for (int i = 1; i <= n; i++) {
      scanf("%s", ch[i] + 1);
      for (int j = 1; j <= n; j++)
        if (ch[i][j] == '.') rp[i] = 1;
    }
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= n; j++)
        if (ch[j][i] == '.') cp[i] = 1;
    bool rok, cok;
    rok = cok = 0;
    int k;
    for (k = 1; k <= n; k++)
      if (rp[k] == 0) break;
    if (k > n) rok = 1;
    for (k = 1; k <= n; k++)
      if (cp[k] == 0) break;
    if (k > n) cok = 1;
    if (rok == 0 && cok == 0) {
      puts("-1");
      continue;
    }
    if (rok) {
      for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++)
          if (ch[i][j] == '.') {
            cout << i << " " << j << endl;
            break;
          }
      }
    } else {
      for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++)
          if (ch[j][i] == '.') {
            cout << j << " " << i << endl;
            break;
          }
      }
    }
  }
  return 0;
}
