#include <bits/stdc++.h>
 
using namespace std;
 
int main()
{
  int n=0;
  cin>>n;
  vector<string> v(n);
  for (int i=0;i<n;i++) {
    cin>>v[i];
  }
  vector<int> pos(n,-1);
  for (int i=0;i<n;i++) {
    for (int j=0;j<n;j++) {
      if (v[i][j]=='.') {
    pos[i]=j;
      }
    }
  }
  for (int i=0;i<n;i++) {
    if (pos[i]==-1) {
      cout<<-1<<endl;
      exit(0);
    }
  }
  for (int i=0;i<n;i++) {
    cout<<i+1<<" "<<pos[i]+1<<endl;
  }
}

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