// MagicDark
#include <bits/stdc++.h>
#define debug cerr << "\33[32m[" << __LINE__ << "]\33[m "
#define SZ(x) ((int) x.size() - 1)
#define all(x) x.begin(), x.end()
#define ms(x, y) memset(x, y, sizeof x)
#define F(i, x, y) for (int i = (x); i <= (y); i++)
#define DF(i, x, y) for (int i = (x); i >= (y); i--)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
template <typename T> T& chkmax(T& x, T y) {return x = max(x, y);}
template <typename T> T& chkmin(T& x, T y) {return x = min(x, y);}
template <typename T> T& read(T &x) {
	x = 0; int f = 1; char c = getchar();
	for (; !isdigit(c); c = getchar()) if (c == '-') f = - f;
	for (; isdigit(c); c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
	return x *= f;
}
const int N = 210;
int n, m, k;
signed main() {
	ios::sync_with_stdio(0); // don't use puts
	cin.tie(0), cout.tie(0);
	cin >> n >> m >> k;
	map <string, vector <pair <int, int>>> mp;
	F(i, 1, n) {
		string st;
		cin >> st;
		F(j, 1, m) {
			int pos = (j - 1) * k;
			mp[st.substr(pos, k)].emplace_back(i, j);
		}
	}
	for (auto [a, b]: mp)
		if (b.size() == 1) {
			cout << b.front().first << ' ' << b.front().second;
		}
	return 0;
}
/* why?
*/