#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
const int nmax=2005;
int dp[nmax][nmax];
int v[nmax];
int n,p,q,i,j,p1,p2,val;
bool check(int val)
{
for(i=1;i<=n;i++)
for(j=0;j<=p;j++)
dp[i][j]=q+1;
p1=p2=1;
for(i=1;i<=n;i++)
{
while(v[i]-v[p1]+1>val)
p1++;
while(v[i]-v[p2]+1>2*val)
p2++;
for(j=1;j<=p;j++)
dp[i][j]=min(dp[p1-1][j-1],dp[p2-1][j]+1);
dp[i][0]=dp[p2-1][0]+1;
}
for(i=0;i<=p;i++)
if(dp[n][i]<=q)
return 1;
return 0;
}
int main()
{
//freopen("data.in","r",stdin);
ios_base::sync_with_stdio(false);
cin>>n>>p>>q;
for(i=1;i<=n;i++)
cin>>v[i];
sort(v+1,v+n+1);
if(p+q>=n)
{
cout<<"1";
return 0;
}
val=(1<<29)-1;
for(int p=28;p>=0;p--)
if(check(val-(1<<p)))
val-=(1<<p);
cout<<val;
return 0;
}
