#include <bits/stdc++.h>

using namespace std;

const int N = 205;

string s[N];

signed main() {
    int n, m, k; scanf("%d%d%d", &n, &m, &k);
    for (int i = 1; i <= n; ++i) {
        cin >> s[i];
    }
    map<string, vector< pair<int, int> > > M;
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
            M[s[i].substr((j - 1) * k, k)].push_back({i, j});
        }
    }
    for (auto [x, y] : M) {
        if (y.size() == 1) {
            printf("%d %d\n", y[0].first, y[0].second);
        }
    }
    return 0;
}