#include <bits/stdc++.h>

#define ll long long
#define pb push_back
#define f first
#define s second
#define sz(x) (int)(x).size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define ios ios_base::sync_with_stdio(false);cin.tie(NULL)
#define ld long double

using namespace std;

mt19937 rng(time(NULL));

int main()
{
	int n,m,k;
	cin >> n >> m >> k;
	map<string,int> cnt;
	vector<string> a(n);
	vector<vector<string>> mat(n);
	for(int i=0;i<n;i++){
		cin >> a[i];
		for(int j=0;j<m;j++){
			mat[i].pb(a[i].substr(j*k,k));
			cnt[mat[i][j]]++;
		}
	}
	string koji;
	for(auto p:cnt)if(p.s==1)koji=p.f;
	for(int i=0;i<n;i++){
		for(int j=0;j<m;j++){
			if(mat[i][j]==koji){
				cout << i+1 << " " << j+1 << endl;
			}
		}
	}
	return 0;
}