#include <bits/stdc++.h>
using namespace std;
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii ;
typedef pair<ll, ll> pll ;
typedef vector<pii> vii ;
typedef vector<int> veci ;
typedef vector<pll> vll ;
typedef vector<ll> vecll;
// find_by_order order_of_key
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define F first
#define S second
#define pb push_back
#define endl '\n'
#define Mp make_pair
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " = " << x << endl
#define set_dec(x) cout << fixed << setprecision(x);
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("in.txt" , "r" , stdin) ; freopen("out.txt" , "w" , stdout);
#define lb lower_bound
#define ub upper_bound
#define for1(n) for(int i=1;i<=n;i++)
#define for0(n) for(int i=0;i<n;i++)
#define forn(n) for(int i=n;i>0;i--)
#define pq priority_queue <pii, vector<pii>, greater<pii>>
const ll mod = 1e9+7 ;// 998244353 ;// 1e9+9;
ll inf=1e18;
const int N=2e3+100,L=21,bs=701;
int A[N],B[N],C[N],D[N],E[N],n,m,k,q,p,dp[N][N],pre[N],dist[N],vis[N];
vector<int>g[N];
bool check(int w){
for(int i=2;i<=n+1;i++)for(int j=0;j<=p;j++)dp[i][j]=q+1;
for(int i=1;i<=n;i++){
int t1=lb(A+i,A+n+1,A[i]+w)-A;
int t2=lb(A+i,A+n+1,A[i]+w*2)-A;
for(int j=0;j<=p;j++){
dp[t1][j+1]=min(dp[t1][j+1],dp[i][j]);
dp[t2][j]=min(dp[t2][j],dp[i][j]+1);
}
}
return (dp[n+1][p]<=q);
}
int main(){
fast_io
cin>>n>>p>>q;
if(p+q>=n)return cout<<"1\n",0;
for1(n)cin>>A[i];
sort(A+1,A+n+1);
int l=0,r=mod/(p+q*2);
while(r-l!=1){
int mid=(l+r)>>1;
if(check(mid)==0)l=mid;
else r=mid;
}
cout<<l+1<<endl;
}
