#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
const int maxn = 4040;
int n, m, k;
string s[maxn];
void solve() {
cin >> n >> m >> k;
for(int i = 1; i <= n; i++) {
cin >> s[i];
}
for(int i = 1; i <= n; i++) {
bool ok = true;
for(int j = 1; j <= n; j++) {
if(i == j) continue;
int cnt = 0;
for(int x = 0; x < m; x++) {
if(s[i][x] != s[j][x]) cnt++;
}
if(cnt != k) ok = false;
}
if(ok) {
cout << i << endl;
return;
}
}
}
int32_t main() {
ios::sync_with_stdio(false); cin.tie(0);
// freopen("in.in", "r", stdin);
// freopen("out.out", "w", stdout);
int tt = 1;
// cin >> tt;
while(tt--) {
solve();
}
}
