#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
using ll=long long;
using vi=vector<int>;
using vl=vector<ll>;
using pii=pair<int,int>;
#define pb push_back
#define all(a) begin(a),end(a)

const int N=300010,MOD=1e9+7;
const char en='\n';
const ll LLINF=1ll<<60;

int n,m,k;
string h[N];
map<string,vector<pii>> mp;

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin>>n>>m>>k;
	for (int i=0;i<n;++i)
	{
		for (int j=0;j<m;++j)
		{
			string cu;
			for (int u=0;u<k;++u)
			{
				char c;
				cin>>c;
				cu.pb(c);
			}
			mp[cu].pb({i,j});
		}
	}
	for (auto x: mp) if (x.y.size()==1) cout<<x.y[0].x+1<<' '<<x.y[0].y+1<<en;
}