#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> ti;
typedef vector<ll> li;
typedef vector<li> lii;
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define LSOne(s) ((s)&(-s))
#define all(x) x.begin(),x.end()
ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;
int n,m,k;
vector<string> a;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin>>n>>m>>k;
a.resize(n);
REP(i,0,n)cin>>a[i];
REP(i,0,n){
bool flag=1;
REP(j,0,n)if(i!=j){
int cnt=0;
REP(x,0,m)if(a[i][x]!=a[j][x])cnt++;
if(cnt!=k){
flag=0;
break;
}
}
if(flag){
cout<<i+1;
return 0;
}
}
}
