#include <algorithm>
#include<bits/stdc++.h>
using namespace std;
#define int int64_t
#define pb push_back
#define st first
#define nd second
#define pii pair<int, int>
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
string tab[4109];
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, m, K;
cin >> n >> m >> K;
for(int i=1;i<=n;i++) cin >> tab[i];
vector<int> v1;
vector<int> v2;
for(int i=1;i<=n;i++) v1.pb(i), v2.pb(i);
random_shuffle(all(v1));
random_shuffle(all(v2));
for(int i=0;i<n;i++) {
bool ans = true;
for(int j=0;j<n;j++) {
if(v1[i]==v2[j]) continue;
int cnt = 0;
for(int k=0;k<m;k++) {
if(tab[v1[i]][k]!=tab[v2[j]][k]) cnt++;
}
if(cnt!=K) {
ans = false;
break;
}
}
if(ans) {
cout << v1[i] << "\n";
return 0;
}
}
}
