#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<string>
#include<map>
#include<deque>
#include<cmath>
#include<vector>
#include<queue>
#include<stack>
#include<set>
#include<iomanip>

using namespace std;

int main(){
	int n,m,k;
	string s;
	cin>>n>>m>>k;
	map<string,tuple<int,int,int>> mp;
	for(int ii=1;ii<=n;ii++){
		cin>>s;
		for(int i=0;i<s.length();i+=k){
			string ss;
			for(int j=0;j<k;j++){
				ss=ss+s[i+j];
			}
			get<0>(mp[ss])++;
			get<1>(mp[ss])=ii;
			get<2>(mp[ss])=i/k+1;
		}
		
	}
	string ans;
	for(auto t:mp){
		if(get<0>(t.second)==1){
			cout<<get<1>(t.second)<<" "<<get<2>(t.second)<<endl;
		}
	}
	return 0;
}