#include <bits/stdc++.h>
#define pb emplace_back
#define fst first
#define scd second
#define mkp make_pair
#define uint unsigned
#define mems(a, x) memset((a), (x), sizeof(a))

using namespace std;
typedef long long ll;
typedef double db;
typedef unsigned long long ull;
typedef long double ldb;
typedef pair<ll, ll> pii;

const int maxn = 2020;

int n, m, K;
char s[maxn][maxn];

void solve() {
	scanf("%d%d%d", &n, &m, &K);
	for (int i = 1; i <= n; ++i) {
		scanf("%s", s[i] + 1);
	}
	int cnt = 0;
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= m; ++j) {
			bool fl = 1;
			for (int k = 0; k < K && fl; ++k) {
				fl &= (s[1][k + 1] == s[i][(j - 1) * K + k + 1]);
			}
			cnt += (!fl);
		}
	}
	if (cnt > 1) {
		puts("1 1");
		return;
	}
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= m; ++j) {
			bool fl = 1;
			for (int k = 0; k < K && fl; ++k) {
				fl &= (s[1][k + 1] == s[i][(j - 1) * K + k + 1]);
			}
			if (!fl) {
				printf("%d %d\n", i, j);
				return;
			}
		}
	}
}

int main() {
	int T = 1;
	// scanf("%d", &T);
	while (T--) {
		solve();
	}
	return 0;
}