#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;

#define all(x) (x).begin(), (x).end()

int main() {
#ifndef ONLINE_JUDGE
  freopen("a.txt", "r", stdin);
#endif
  ios_base::sync_with_stdio(false);

  int n, m, k;
  cin >> n >> m >> k;
  vector<vector<string>> s(n, vector<string>(m));
  for (int i = 0; i < n; ++i)
    for (int j = 0; j < m; ++j) {
      s[i][j].resize(k);
      for (int t = 0; t < k; ++t)
        cin >> s[i][j][t];
    }

  map<string, int> cnt;
  for (int i = 0; i < n; ++i)
    for (int j = 0; j < m; ++j)
      cnt[s[i][j]]++;

  for (int i = 0; i < n; ++i)
    for (int j = 0; j < m; ++j)
      if (cnt[s[i][j]] == 1) {
        cout << i + 1 << " " << j + 1 << "\n";
      }


  return 0;
}