#include <bits/stdc++.h>
using namespace std;

void doWork(){
    int n , m , k;
    cin >> n >> m >> k;
    string s[n] = {};
    for (int i = 0 ; i < n ; i++){
        cin >> s[i]; 
    } 
    for (int i = 0 ; i < n ; i++){
        bool f =1; 
        for (int j = 0 ; j < n ; j++){
            if (j == i) continue; 
            int cnt = 0; 
            for (int l = 0 ; l < m ; l++){
                if (s[i][l] != s[j][l]) cnt++; 
            }
            if (cnt != k) {f = 0; break;}
        }
        if (f) {cout << i+1; return;}
    }
}

signed main(){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    doWork(); cout << '\n'; 
}