#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;   }   