#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> ti;
typedef vector<ll> li;
typedef vector<li> lii;
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define LSOne(s) ((s)&(-s))
ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;
int n,p,q,dp[2001][2001];
vi a;
bool solve(int m){
REP(i,0,p+1)REP(j,0,q+1){
int x=0,y=0;
if(i-1>=0){
if(dp[i-1][j]==n)x=n;
else x=upper_bound(a.begin()+dp[i-1][j],a.end(),a[dp[i-1][j]]+m-1)-a.begin();
}
if(j-1>=0){
if(dp[i][j-1]==n)y=n;
else y=upper_bound(a.begin()+dp[i][j-1],a.end(),a[dp[i][j-1]]+min(2*m-1,inf-a[dp[i][j-1]]))-a.begin();
}
dp[i][j]=max(x,y);
}
return dp[p][q]==n;
}
int BS(int l,int r){
if(l==r)return l;
int m=(l+r)/2;
if(solve(m))return BS(l,m);
else return BS(m+1,r);
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin>>n>>p>>q;
a.resize(n);
REP(i,0,n)cin>>a[i];
sort(a.begin(),a.end());
if(p+q>=n){
cout<<1;
return 0;
}
cout<<BS(1,1000000000);
}
