#include <bits/stdc++.h>
#define sz(x) (int)(x).size()
#define all(x) (x).begin(),(x).end()
#define All(x) (x).begin() + 1,(x).end()
#define ls(x) (x << 1)
#define rs(x) (x << 1 | 1)
#define fi first
#define se second
using ull = unsigned long long;
using ll = long long;
using F = long double;
using namespace std;
template <typename T>
void DE(const T& v) {
    int n = v.size();
    for (int i = 0; i < n; i++) {
        std::cerr << " ["[i == 0] << v[i];
    }
    std::cerr << "]\n";
}


int main(){ 
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n,m,k;
    cin >> n >> m >> k;
    int p = m / k;
    vector<vector<string>> a(n + 1, vector<string>(m + 1));
    map<string, int> cnt;
    for (int i = 1; i <= n; i++) {
        string s;
        cin >> s;
        for (int j = 0; j < sz(s); j += k) {
            string sub = s.substr(j, k);
            a[i][j / k + 1] = sub;
            cnt[sub]++;
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (cnt[a[i][j]] == 1) {
                cout << i << " " << j << '\n';
                return 0;
            }

        }
    }
    return 0;
}