#include <bits/stdc++.h>

#define forn(i, n) for (int i = 0; i < int(n); ++i)
#define fore(i, l, r) for (int i = int(l); i < int(r); ++i)

using namespace std;

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n, m, k;
	cin >> n >> m >> k;
	vector<string> s(n);
	for(int i = 0; i < n; i++) cin >> s[i];
	map<string, vector<pair<int, int>>> mp;
	for(int i = 0; i < n; i++)
		for(int j = 0; j < m * k; j += k)
		{
			mp[s[i].substr(j, k)].push_back(make_pair(i, j / k));
		}
	for(auto x : mp)
		if(x.second.size() == 1)
		{
			auto p = x.second[0];
			cout << p.first + 1 << " " << p.second + 1 << endl;
		}
}