#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn=2e3+5;
int n,a,b;
int h[maxn],r[maxn],r2[maxn];
int dp[maxn][maxn];
bool check(int w){
memset(dp,0,sizeof(dp));
for(int i=1;i<=n;i++){
r[i]=upper_bound(h+1,h+n+1,h[i]+w-1)-h-1;
r2[i]=upper_bound(h+1,h+n+1,h[i]+2*w-1)-h-1;
}
dp[0][0]=0;
for(int i=0;i<=a;i++){
for(int j=0;j<=b;j++){
if(i==0&&j==0) continue;
if(i>0) dp[i][j]=max(dp[i][j],r[dp[i-1][j]+1]);
if(j>0) dp[i][j]=max(dp[i][j],r2[dp[i][j-1]+1]);
if(dp[i][j]>=n) return true;
}
}
if(dp[a][b]==n) return true;
return false;
}
int main(){
cin>>n>>a>>b;
for(int i=1;i<=n;i++) cin>>h[i];
if(a+b>=n){
cout<<1;
return 0;
}
sort(h+1,h+n+1);
int l=1,r=1e9,ans=0;
while(l<=r){
int m=(l+r)/2;
if(check(m)){
ans=m;
r=m-1;
}
else l=m+1;
}
cout<<ans;
}
