#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 4100 + 5;
const int inf = 1e9;
const int mod = 1e9 + 7;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n, m, k;
cin >> n >> m >> k;
vector<string> s(n);
map<string, int> mp;
for (int i = 0; i < n; i++) {
cin >> s[i];
mp[s[i]]++;
}
for (int i = 0; i < n; i++) {
if (mp[s[i]] > 1) continue;
map<string, int> bio;
int moze = 1;
for (int j = 0; j < n; j++) {
if (i == j || bio[s[j]] == 1) continue;
int r = 0;
for (int p = 0; p < m; p++) {
if (s[i][p] != s[j][p]) r += 1;
if (r > k || r + m - p - 1 < k) {
moze = 0;
break;
}
}
if (moze == 0) break;
bio[s[j]] = 1;
}
if (moze == 0) continue;
cout << i + 1 << en;
return 0;
}
return 0;
}
