#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include <map>
#define mems(x, v) memset(x, v, sizeof x)
#define mcpy(x, y) memcpy(x, y, sizeof x)
using namespace std;
typedef pair <int, int> pii;
typedef long long ll;
typedef unsigned long long ull;
typedef long double wisdom;

map <string, vector <pii>> str;
int main() {
	int n, m, t; cin >> n >> m >> t;
	for (int i = 1; i <= n; i++) for (int j = 1; j <= m; j++) {
		string s = ""; for (int k = 1; k <= t; k++) {char x; cin >> x; s += x;}
		str[s].push_back({i, j});
	}
	for (auto [t, vec] : str) if (vec.size() == 1) return cout << vec[0].first << ' ' << vec[0].second, 0;
	return 0;
}