#include <bits/stdc++.h>
using namespace std;

using ui = unsigned;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
#define rep(i,l,r) for(int i=(l);i<=(r);++i)
#define per(i,l,r) for(int i=(l);i>=(r);--i)
#define repn(i,n) for(int i=0;i<(n);++i)
#define sizc(x) ((int)(x).size())
#define allc(x) (x).begin(),(x).end()
#define fir first
#define sec second

int n,m,k;
map<string,int> mp1;
map<string,pair<int,int>> mp2;

signed main(){
	// freopen(".in","r",stdin);
	// freopen(".out","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

    cin>>n>>m>>k;
    rep(i,1,n)rep(j,1,m){
        string s;repn(_,k){char ch;cin>>ch;s+=ch;}
        ++mp1[s];
        mp2[s]={i,j};
    }
    for(auto p:mp1)if(p.sec==1)cout<<mp2[p.fir].fir<<' '<<mp2[p.fir].sec<<'\n';
}