#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
long long max(long long a, long long b) {
  if (a > b) {
    return a;
  } else {
    return b;
  }
}
long long min(long long a, long long b) {
  if (a < b) {
    return a;
  } else {
    return b;
  }
}
long long sz(vector<long long> v) {
  if (v.empty()) {
    return 0;
  } else {
    return v.size();
  }
}
long long sz(set<long long> v) {
  if (v.empty()) {
    return 0;
  } else {
    return v.size();
  }
}
long long sz(vector<pair<long long, long long> > v) {
  if (v.empty()) {
    return 0;
  } else {
    return v.size();
  }
}
long long power(long long b, long long e) {
  if (e == 0) return 1;
  if (e % 2)
    return ((b * power((b) * (b), (e - 1) / 2)));
  else
    return power((b) * (b), e / 2);
}
long long modpower(long long b, long long e, long long q) {
  long long MOD = q;
  if (e == 0) return 1;
  if (e % 2)
    return ((b % MOD) * modpower((b % MOD) * (b % MOD), (e - 1) / 2, q)) % MOD;
  else
    return modpower((b % MOD) * (b % MOD), e / 2, q) % MOD;
}
void dpv(vector<long long> v) {
  for (long long i = 0; i < v.size(); i++) {
    cout << v[i] << " ";
  }
  cout << '\n';
}
void dpv(vector<pair<long long, long long> > v) {
  for (long long i = 0; i < v.size(); i++) {
    cout << v[i].first << " " << v[i].second << '\n';
  }
}
void dpv(set<long long> v) {
  for (auto i : v) {
    cout << i << " ";
  }
  cout << '\n';
}
void oblivious() {
  long long n;
  cin >> n;
  string s[n];
  char c[n][n];
  for (long long i = 0; i < n; i++) {
    cin >> s[i];
    for (long long j = 0; j < s[i].length(); j++) {
      c[i][j] = s[i][j];
    }
  }
  long long r[n], co[n];
  memset(r, 0, sizeof(r));
  memset(co, 0, sizeof(co));
  for (long long i = 0; i < n; i++) {
    for (long long j = 0; j < n; j++) {
      if (c[i][j] == '.') {
        r[i] = 1;
        co[j] = 1;
      }
    }
  }
  long long f1 = 1;
  long long f2 = 1;
  for (long long i = 0; i < n; i++) {
    if (r[i] == 0) {
      f1 = 0;
      break;
    }
  }
  for (long long i = 0; i < n; i++) {
    if (co[i] == 0) {
      f2 = 0;
      break;
    }
  }
  if (f1 || f2) {
    if (f1 && f2) {
      for (long long i = 0; i < n; i++) {
        for (long long j = 0; j < n; j++) {
          if (c[i][j] == '.') {
            cout << i + 1 << " " << j + 1 << '\n';
            break;
          }
        }
      }
    } else if (f1) {
      for (long long i = 0; i < n; i++) {
        for (long long j = 0; j < n; j++) {
          if (c[i][j] == '.') {
            cout << i + 1 << " " << j + 1 << '\n';
            break;
          }
        }
      }
    } else if (f2) {
      for (long long i = 0; i < n; i++) {
        for (long long j = 0; j < n; j++) {
          if (c[j][i] == '.') {
            cout << j + 1 << " " << i + 1 << '\n';
            break;
          }
        }
      }
    }
  } else {
    cout << "-1" << '\n';
  }
}
signed main() {
  long long t = 1;
  while (t--) {
    oblivious();
  }
  return 0;
}
