#include <bits/stdc++.h>
using namespace std;
const int N = 2001;
int n,p,q;
int a[N];
long long l = 1,r = 1e9;
int dp[N][N],sm[N],bg[N];
bool solve(int x)
{
int now = 1;
for(int i = 1;i <= n;i++)
{
while(now<n and a[now+1]-a[i]+1<=x) now++;
sm[i] = now;
}
now = 1;
for(int i = 1;i <= n;i++)
{
while(now<n and a[now+1]-a[i]+1<=x*2) now++;
bg[i] = now;
}
for(int i = 0;i <= n;i++) for(int j = 0;j <= n;j++)
{
dp[i][j] = 0;
if(i) dp[i][j] = max(dp[i][j],sm[dp[i-1][j]+1]);
if(j) dp[i][j] = max(dp[i][j],bg[dp[i][j-1]+1]);
if(dp[i][j]==n and i<=p and j<=q) return true;
}
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+n+1);
while(l<r)
{
long long m = (l+r)/2LL;
if(solve(m)) r = m;
else l = m+1;
}
cout << l;
}
