#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast,inline") // Ofast = O3,fast-math,allow-store-data-races,no-protect-parens
#pragma GCC optimize("unroll-loops")
#pragma GCC target("bmi,bmi2,lzcnt,popcnt") // bit manipulation
#pragma GCC target("movbe") // byte swap
#pragma GCC target("aes,pclmul,rdrnd") // encryption
#pragma GCC target("avx,avx2,f16c,fma,sse3,ssse3,sse4.1,sse4.2")
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define rep(i, a, b) for (int i = (a); i < int(b); i++) // in , ex
#define rrep(i, a, b) for (int i = (a)-1; i >= int(b); i--) // ex, in
#define pb push_back
#define all(x) x.begin(), x.end()
inline void fast()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
const ll INF = 100000000000000000; // 1e17
const ll MOD = 1e9 + 7;
//
random_device rd;
mt19937 rng(rd());
template <typename T>
inline T randint(T lo, T hi) { return uniform_int_distribution<T>(lo, hi)(rng); }
#define int ll
#define float double
//
int N, M, K;
vector<string> ns;
vector<bool> na;
int32_t main()
{
fast();
cin >> N >> M >> K;
ns.assign(N, "");
rep(i, 0, N) cin >> ns[i];
na.assign(N, true);
rep(i, 0, N)
{
if (!na[i])
continue;
rep(j, 0, N)
{
if (j == i)
continue;
int cnt = 0;
rep(k, 0, M)
{
if (ns[i][k] != ns[j][k])
cnt++;
}
if (cnt != K)
{
na[i] = false;
na[j] = false;
break;
}
}
if (na[i])
{
cout << i + 1 << "\n";
return 0;
}
}
}
