#include<bits/stdc++.h>
using namespace std;
int a[2005],n,p,q;
int len1[2005],len2[2005],dp[2005][2005];
bool check(int w)
{
for(int i=1;i<=n;++i){
len1[i]=len2[i]=i;
for(int j=i+1;j<=n;++j){
if(a[i]+w-1>=a[j])len1[i]=j;
if(a[i]+2*w-1>=a[j])len2[i]=j;
}
}
len1[n+1]=len2[n+1]=n;
dp[0][1]=len2[1];dp[1][0]=len1[1];
for(int i=1;i<=p;++i){
for(int j=1;j<=q;++j){
int pos1=dp[i-1][j],pos2=dp[i][j-1];
if(pos1>=n || pos2>=n)dp[i][j]=n;
pos1++;
pos2++;
dp[i][j]=max(len1[pos1],len2[pos2]);
}
}
if(dp[p][q]>=n)return true;
else return false;
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n>>p>>q;
for(int i=1 ;i<=n;++i)cin>>a[i];
sort(a+1,a+1+n);
if(p+q>=n){
cout<<"1";
return 0;
}
int l=0,r=1e9;
while(l+1<r){
int mid=(l+r)/2;
if(check(mid))r=mid;
else l=mid;
}
//cout<<check(4)<<"\n****"<<endl;
int ans=1e9;
if(check(r))ans=min(ans,r);
if(check(l))ans=min(ans,l);
cout<<ans;
}
