/*input
4 3 1
ACC
CCA
ACA
AAA
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
//order_of_key #of elements less than x
// find_by_order kth element
typedef long long int ll;
#define ld long double
#define pii pair<int,int>
typedef tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
const ll maxn=2e5+5;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
const int INF=0x3f3f3f3f;
const ll MOD=998244353;
const ld PI=acos(-1);
const ld eps=1e-9;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
out<<P.f+1<<' '<<P.s+1;
return out;
}
template<typename T>
ostream& operator<<(ostream& out,vector<T> V){
REP(i,sz(V)) out<<V[i]<<((i!=sz(V)-1)?"\n":"");
return out;
}
int mult(ll a,ll b){
if(a<0) a+=MOD;
return (a*b)%MOD;
}
ll mypow(ll a,ll b){
if(b<=0) return 1;
ll res=1LL;
while(b){
if(b&1) res=mult(res,a);
a=mult(a,a);
b>>=1;
}
return res;
}
string arr[maxn];
bool vis[maxn];
int k;
int df(int i,int j){
int cnt=0;
REP(z,sz(arr[i])){
if(arr[i][z]!=arr[j][z]) ++cnt;
if(cnt>k or cnt+(sz(arr[i])-z-1)<k) break;
}
return cnt;
}
mt19937 rng(3242);
int32_t main(){
ios::sync_with_stdio(false),cin.tie(0);
int n,m;
cin>>n>>m>>k;
REP(i,n) cin>>arr[i];
REP(i,n){
vector<int> v;
REP(j,n) if(j!=i) v.pb(j);
shuffle(ALL(v),rng);
bool bad=0;
for(int x:v){
if(df(i,x)!=k){
bad=1;
break;
}
}
if(!bad){
cout<<i+1;
return 0;
}
}
}
