#include<bits/stdc++.h>
using namespace std;
using ll=long long;
int n,p,q;
int a[2005];
int dp[2005][2005];
bool check(int mid){
memset(dp,0,sizeof dp);
for(int i=0;i<=p;++i)
for(int j=0;j<=q;++j){
int x,y;
x=y=n;
if(i){
x=dp[i-1][j];
dp[i][j]=max(dp[i][j],x);
}
if(j){
y=dp[i][j-1];
dp[i][j]=max(dp[i][j],y);
}
if(i and x<n){
int X=a[x+1]+mid-1;
int x1=upper_bound(a+1,a+n+1,X)-a-1;
dp[i][j]=max(dp[i][j],x1);
}
if(j and y<n){
int X=a[y+1]+2*mid-1;
int x1=upper_bound(a+1,a+n+1,X)-a-1;
dp[i][j]=max(dp[i][j],x1);
}
if(dp[i][j]==n)return 1;
}
return 0;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
cin>>n>>p>>q;
p=min(p,n);
q=min(q,n);
for(int i=1;i<=n;++i)cin>>a[i];
sort(a+1,a+n+1);
int l=1,r=5e8,mid,ans;
while(l<=r){
mid=(l+r)>>1;
if(check(mid)){
ans=mid;
r=mid-1;
}else l=mid+1;
}
cout<<ans<<'\n';
}
