#include <bits/stdc++.h>
#define rep(i,x,y) for(int i = x; i <= y; i++)
#define mid ((l + r) >> 1)
#define lch (rt << 1)
#define rch (rt << 1 | 1)

using namespace std;

using u32 = unsigned;
using i64 = long long;
using u64 = unsigned long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    int n, m, k;
    cin >> n >> m >> k;

    vector<string> s(n);
    rep(i,0,n-1) cin >> s[i];

    const string base = s[0].substr(0, k);

    rep(i,0,n-1) {
        for (int j = 0; j < m; j++) {
            if (s[i].substr(j * k, k) != base) {
                cout << i + 1 << ' ' << j + 1 << '\n';
                return 0;
            }
        }
    }

    return 0;
}