#include <bits/stdc++.h>
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define ll long long
using namespace std;
const ll N=2005,INF=1e9;
ll a[N],l,r,x,y,z,ans,t,n,q,mx,mn,k,p,dp[N][N];
bool ok,okk;
bool check(ll x){
for (int i=0; i<=n; i++){
for (int j=0; j<=p; j++) dp[i][j]=INF;
}
for (int i=0; i<=p; i++) dp[0][i]=0;
for (int i=1; i<=n; i++){
for (int j=0; j<=p; j++){
// patara
if (j!=0){
int ind=lower_bound(a+1,a+n+1,a[i]-x+1)-a-1;
dp[i][j]=min(dp[i][j],dp[ind][j-1]);
}
//didi
int ind=lower_bound(a+1,a+n+1,a[i]-2*x+1)-a-1;
dp[i][j]=min(dp[i][j],dp[ind][j]+1);
// cout<<i<<" "<<j<<" "<<dp[i][j]<<" IND: "<<ind<<endl;
}
}
// cout<<x<<" "<<dp[n][p]<<endl;
if (dp[n][p]<=q) return 1;
return 0;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0),cout.tie(0);
t=1;
cin >> n >> p >> q;
for (int i=1; i<=n; i++){
cin >> a[i];
}
if (p+q>=n){
cout<<1<<endl; return 0;
}
sort(a+1,a+n+1);
ans=0;
for (int i=30; i>=0; i--){
ans+=(1<<i);
if (check(ans)==1) ans-=(1<<i);
}
cout << ans+1 << endl;
}
