#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize ("unroll-loops,Ofast,O3")
#pragma GCC target("avx,avx2,fma")
#define F first
#define S second
#define sz(x) (int)x.size()
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define NFS ios_base::sync_with_stdio(0) , cin.tie(0) , cout.tie(0) ;
#define file(s) if (fopen(s".in", "r")) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout)
typedef long long ll;
const int E = 1e6+777;
const long long inf = 1e18+777;
const int N = 4800;
const int MOD = 1e9+7;
const bool I = 1;
int n, m, k;
string s[N];
int main(){
NFS;
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 mx = 0;
for(int p = 0; p < m; ++p){
mx += (s[i][p] != s[j][p]);
}
if(mx != k){
ok = false;
break;
}
}
if(ok){
cout << i << '\n';
return 0;
}
}
};
