//Cut it out, you've already lost.
#include<bits/stdc++.h>
using namespace std;
const int maxn=500005;
int n,m,k,T,ans,flg;
int a[maxn];
string s;
map<string,vector<pair<int,int>>>mp;
int main(){
	scanf("%d%d%d",&n,&m,&k);
	for(int i=1;i<=n;i++){
		cin>>s;
		for(int j=0;j<m;j++){
			string t;
			t.resize(k);
			for(int l=0;l<k;l++)
				t[l]=s[j*k+l];
			mp[t].emplace_back(make_pair(i,j+1));
		}
	}
	for(map<string,vector<pair<int,int>>>::iterator it=mp.begin();it!=mp.end();it++)
		if(it->second.size()==1){
			printf("%d %d\n",it->second[0].first,it->second[0].second);
			break;
		}
	return 0;
}