/*
Editor: Abdelrahman Hossam
Nickname: Blobo2_Blobo2
IOI next year isA :)
*/
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,sse4.2,popcnt,abm,mmx,avx2,tune=native")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-funroll-all-loops,-fpeel-loops,-funswitch-loops")
#include<bits/stdc++.h>
using namespace std;
//#define int long long
#define endl "\n"
#define all(v) v.begin(),v.end()
#define gen(arr,n,nxt) generate(arr,arr+n,nxt)
#define Blobo2_el_7akim_elly_3ayz_yro7_IOI_w_3ayz_yakol_jilaty ios_base::sync_with_stdio(false);cin.tie(0);
const int mo=1e9+7,INF=1e18;
int nxt(){int x;cin>>x;return x;}
int n,sm,big,arr[2001],dp[2001][2001],mid;
int BS(int x,int idx){
int s=idx,e=n-1;
while(s<=e){
int mid=(s+e)>>1;
if(arr[mid]>x)e=mid-1;
else s=mid+1;
}
return e;
}
int check(int idx=0,int small=0){
if(small>sm)
return INT_MAX;
if(idx>=n)
return 0;
int &ret = dp[idx][small];
if(ret!=-1)return ret;
ret=INT_MAX;
int r1 = (arr[idx] + mid) -1 ,r2 = (arr[idx] + (mid*2)) -1;
int idx2 = BS(r1,idx),idx3 = BS(r2,idx);
return ret = min(check(idx2+1,small+1),
check(idx3+1,small)+1);
}
bool ok(){
for(int i=0;i<n;i++)for(int j=0;j<=sm;j++)dp[i][j]=-1;
check();
if(dp[0][0] <= big)
return 1;
return 0;
}
signed main(){
Blobo2_el_7akim_elly_3ayz_yro7_IOI_w_3ayz_yakol_jilaty
n=nxt(),sm=nxt(),big=nxt();
if(big+sm>=n){
cout<<1;
return 0;
}
if(sm>n)sm=n;
if(big>n)big=n;
gen(arr,n,nxt);
sort(arr,arr+n);
int s=1,e=1e9;
while(s<=e){
mid=(s+e)>>1;
if(ok()){
e=mid-1;
}
else s=mid+1;
}
cout<<s;
return 0;
}
