#include<bits/stdc++.h>
using namespace std;
#define int long long
int nextp[2005],nextq[2005];
int a[2000+4];
int memo[2005][2005];
int n,p,q;
int dp(int idx,int p){
if(p<0)return 1e18;
if(idx==n+1)return 0;
if(memo[idx][p]!=-1)return memo[idx][p];
return memo[idx][p]=min(dp(nextp[idx],p-1),dp(nextq[idx],p)+1);
}
bool ok(int w){
for(int k=1;k<=n;k++){
nextp[k]=nextq[k]=n+1;
for (int j =k+1; j <=n; j++) {
if (a[j] - a[k] + 1 > w) {
nextp[k] = j;
break;
}
}
for (int j = k+1; j <=n; j++) {
if (a[j] - a[k] + 1 > 2 * w) {
nextq[k] = j;
break;
}
}
}
memset(memo,-1,sizeof memo);
return dp(1,p)<=q;
}
signed main(){
cin>>n>>p>>q;
for(int k=1;k<=n;k++){
cin>>a[k];
}
if(p+q>=n){
cout<<1<<endl;
return 0;
}
sort(a+1,a+n+1);
int l=1,r=1e9,ans=1e9;
while(l<=r){
int mid=(l+r)/2;
if(ok(mid)){
ans=min(ans,mid);
r=mid-1;
}
else{
l=mid+1;
}
}
cout<<ans<<endl;
}
