#include<bits/stdc++.h>
#define int long long 

using namespace std ; 

const int N = 2e6 + 10 , mod = 998244353 ; 
typedef pair<int , int> PII ;
mt19937_64 rng(random_device{}());

void solve(){
	int n, m;
	int k;
	cin >> n >> m >> k;
	map<string, int> mmap;
	map<string, pair<int, int>> mmap2;
	for(int i = 0; i < n; i ++){
		string s;
		cin >> s;
		for(int j = 0; j < k * m; j += k){
			string str = s.substr(j, k);
			//cout << str << endl;
			mmap[str] ++;
			mmap2[str] = {i + 1, j / k + 1};
		}
	}
	for(auto i : mmap){
		if(i.second == 1){
			cout << mmap2[i.first].first << " " << mmap2[i.first].second << endl;
			break;
		}
	}
}

signed main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr), cout.tie(nullptr);
	int t;
	t = 1;
	while(t --){
		solve();
	}
	return 0;
}

/*   /\_/\
*   (= ._.)
*   / >  \>
*/