#include <bits/stdc++.h>

using namespace std;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);

  int n, m, k;
  cin >> n >> m >> k;
  vector<string> a(n + 1);
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }

  string s = a[1].substr(0, k);
  string ans{};
  int cnt = 0, x = 1, y = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < m * k; j += k) {
      string tmp = a[i].substr(j, k);
      if (tmp != s) {
        cnt++;
        x = i, y = j;
      }
    }
  }

  if (cnt == 1) {
    cout << x << " " << y / k + 1 << "\n";
  } else {
    cout << 1 << " " << 1 << "\n";
  }

  return 0;
}