#include <bits/stdc++.h>
using i64 = long long;
using u64 = unsigned long long;
using u32 = unsigned;
using u128 = unsigned __int128;
void solve() {
int n, m, k;
std::cin >> n >> m >> k;
std::vector<std::vector<char>> a(n + 1, std::vector<char>(m + 1));
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
std::cin >> a[i][j];
}
}
for(int i = 1; i <= n; i++) {
int is = 1;
for(int ath = 1; ath <= n; ath++) {
if(i == ath) {
continue;
}
int diff = 0;
for(int x = 1; x <= m; x++) {
diff += (a[i][x] != a[ath][x]);
}
is &= (diff == k);
}
if(is) {
std::cout << i;
return;
}
}
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int t = 1;
//std::cin >> t;
while (t--) {
solve();
}
return 0;
}
