#include<bits/stdc++.h>
#define int long long
#define eb emplace_back
#define mp make_pair
#define DEBUG
using namespace std;
using pii = pair<int, int>;
using piii = pair<int, pii>;
using piiii = pair<pii, pii>;
using i64 = long long;
using u64 = unsigned long long;
using u32 = unsigned int;
const int P = 998244353;const i64 inf = 0x3f3f3f3f3f3f3f3f;
namespace azus{
	int n, m, k;
	string s[205];
	int main(){
		cin >> n >> m >> k;
		for(int i = 1; i <= n; i ++){
			cin >> s[i];
		}
		string cs = "";
		for(int i = 0; i < k; i ++)
			cs += s[1][i];
		// cout << cs << "\n";
		int cnt = 0;
		pii pos = mp(-1, -1);
		for(int i = 1; i <= n; i ++){
			for(int j = 1; j <= m; j ++){
			string ds = "";
				int l = (j - 1) * k, r = j * k - 1;
				for(int c = l; c <= r; c ++)
					ds += s[i][c];
				if(ds != cs){
					cnt ++;
					// cout << cnt << " " << ds << "\n";
					pos = mp(i, j);
				}
			}
		}
		if(cnt != 1) cout << "1 1\n";
		else cout << pos.first << " " << pos.second << "\n";
		return 0;
	}
}
signed main(){
#ifndef DEBUG
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
#endif
	int T = 1;
	while(T --)
		azus::main();
	return 0;
}