#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define int long long
#define pii pair<int,int>
#define vi vector<int>
#define ff first
#define ss second
#define sp << " " <<
#define all(x) x.begin(),x.end()
#define big(x) ((int)(x.size()))
using namespace std;
const int MOD = 998244353, LIM = 1e6+1, inf = 2e18,N = 2e5+1;
void solve() {
int n,m,k;
cin >> n >> m >> k;
vector<string> strs(n+1);
vi stk;
auto calcdiff =[&](int i,int j) -> int {
int ans = 0;
for (int p = 0;p<m;p++) {
ans+=strs[i][p] != strs[j][p];
if (ans > k) return ans;
if (ans+(m-p-1) < k) return ans;
}
return ans;
};
vi ord(n+1);
iota(all(ord),0ll);
vi alive(n+1,1);
for (int i=1;i<=n;i++) cin >> strs[i];
int t = 5;
while (t--) {
shuffle(1+all(ord),mt19937());
stk.clear();
for (int i=1;i<=n;i++) {
int fl = alive[ord[i]];
while (!stk.empty() && calcdiff(stk.back(),ord[i]) != k) {
stk.pop_back();
fl = 0;
}
if (fl) stk.push_back(ord[i]);
}
}
while (!stk.empty()) {
int fl= 1;
for (int j = 1;j<=n;j++) {
if (j != stk.back() && calcdiff(stk.back(),j) != k) {
fl = 0;
break;
}
}
if (fl) {
cout << stk.back() << '\n';
return;
}
stk.pop_back();
}
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0);
int t = 1;
//cin >> t;
while (t --> 0) solve();
}
