#include<iostream>
#include<cstring>
#include<map>
#define int long long
using namespace std;

int N, M, K;
string s[201];
map<string,int> mp;
signed main()
{
    // freopen("testdata.in","r",stdin);
    cin >> N >> M >> K;
    for(int i=1;i<=N;i++)
    {
        cin >> s[i];
        s[i]=" "+s[i];
        for(int j=1;j<=M;j++)
        {
            string tmp="";
            for(int k=(j-1)*K+1;k<=j*K;k++)
            {
                tmp+=s[i][k];
            }
            // cout << "i=" << i << ", j=" << j << ", tmp=" << tmp << '\n';
            mp[tmp]++;
        }
    }
    for(int i=1;i<=N;i++)
    {
        for(int j=1;j<=M;j++)
        {
            string tmp="";
            for(int k=(j-1)*K+1;k<=j*K;k++)
                tmp+=s[i][k];
            if(mp[tmp]==1) {cout << i << " " << j << '\n'; return (0-0);}
        }
    } 
    return (0-0);
}