//Date: 2024-11-16 13:02:51
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int rd() {
    int s=0,m=0;char ch=getchar();
    while(!isdigit(ch)) {if(ch=='-')m=1;ch=getchar();}
    while( isdigit(ch)) s=(s<<3)+(s<<1)+(ch^48),ch=getchar();
    return m?-s:s;
}
bool MBE;
namespace SOLVER {
int n,m,k;string s[205];
map<string,int> mp;
void MAIN() {
    cin>>n>>m>>k;for(int i=1;i<=n;i++) cin>>s[i];
    for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) mp[s[i].substr((j-1)*k,k)]++;
    for(int i=1;i<=n;i++) for(int j=1;j<=m;j++) if(mp[s[i].substr((j-1)*k,k)]==1) cout<<i<<' '<<j<<endl;
}
}
bool MED;
signed main() {
    //freopen(".in","r",stdin);freopen(".out","w",stdout);
    for(int tt=1;tt;tt--) SOLVER::MAIN();
    cerr<<(&MBE-&MED)/1024<<" KB, "<<1000*clock()/CLOCKS_PER_SEC<<" ms\n";
    return 0;
}