// author : thembululquaUwU
// 3.9.2024

#include <bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define endl '\n'

using namespace std;
using ll = long long;
using ii = pair <int, int>;
using vi = vector <int>;

const int MaxN = 2e5;
const int mod = 1e9 + 7;

void maxl(auto &a, auto b) {a = max(a, b);}
void minl(auto &a, auto b) {a = min(a, b);}

void solve(){
    int n, m, k; cin >> n >> m >> k;
    vector <string> s(n);
    for (auto & f : s) cin >> f;
    string cur = "", diff = "";
    pair <int, int> pcur, pdiff;
    int cnti = 0, ok = 0;
    for (auto &f : s){
        int cntj = 0;
        for (int i = 0; i < m * k; i += k){
            string tmp = "";
            for (int j = i; j < i + k; ++ j) tmp = tmp + f[j];
            if (cur == "") {
                cur = tmp;
                pcur = {0, 0};
            }
            else if (tmp != cur){
                if (ok) {
                    cout << cnti + 1 << ' ' << cntj + 1;
                    return;
                }
                if (diff == ""){
                    diff = tmp;
                    pdiff = {cnti, cntj};
                }
                else if (tmp != diff){
                    cout << pdiff.fi + 1 << ' ' << pdiff.se + 1;
                    return;
                }
            }
            else ok = 1;

            ++ cntj;
        }

        ++ cnti;
    }

    if (ok) cout << pdiff.fi + 1 << ' ' << pdiff.se + 1;
    else cout << pcur.fi + 1 << ' ' << pcur.se + 1;
}

int main(){
    if (fopen("pqh.inp", "r")){
        freopen("pqh.inp", "r", stdin);
        freopen("pqh.out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    int t = 1; // cin >> t;
    while (t --) solve();
    return 0;
}