#include <bits/stdc++.h>
using namespace std;
#define ll long long
const ll MAXN=2e3+1,MAXA=5e6+5,INF=1e9,LINF=1e18;
#define fi first
#define se second
#define pll pair<ll,ll>
#define pii pair<int,int>
#define mid (l+r)/2
#define sz(a) int((a).size())
#define all(a) a.begin(),a.end()
#define mod 1000000007LL
#define pb push_back
#define endl "\n"
#define PRINT(x) cerr<<#x<<'-'<<x<<endl<<flush;
#define getunique(v) {sort(all(v)); v.erase(unique(all(v)), v.end());}
#define pb push_back
#define pf push_front
#define ppf pop_front
#define ppb pop_back
#define PRINTvec(x) { cerr<<#x<<"-"; for(int i=0;i<sz(x);i++) cerr<<x[i]<<" "; cerr<<endl; }
#pragma GCC optimize("Ofast")
#pragma GCC target("fma,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
ll n,m,k,p,q,x,y,z,res=INF,l,r;
string s,t;
vector<int> a;
ifstream input;
ofstream output;
#ifdef ONLINE_JUDGE
#define input cin
#define output cout
#endif
bool check(int w){
int idxp=1,idxq=1;
vector<vector<int>> dp(MAXN,vector<int>(MAXN,0)); ///dp[i][j] najmanji broj velikih kamera da bi uz pomoc njih i j kamera prekrili prvih i eventova
for(int i=1;i<=n;i++){
while(a[i]-a[idxp]+1>w) idxp++;
while(a[i]-a[idxq]+1>2*w) idxq++;
///PRINT(idxp); PRINT(idxq);
for(int j=0;j<=p;j++){ ///broj manjih kamera
dp[i][j]=INF;
if(j) dp[i][j]=dp[idxp-1][j-1];
dp[i][j]=min(dp[i][j],dp[idxq-1][j]+1);
}
}
/*
cerr<<"dp:"<<endl;
for(int i=1;i<=n;i++){
for(int j=0;j<=p;j++){
cerr<<dp[i][j]<<" ";
}
cerr<<endl;
}
*/
///PRINT(p);
return dp[n][p]<=q;
}
void solve(){
cin>>n>>p>>q; p=min(n,p); q=min(n,q);
a.resize(n+1);
for(int i=1;i<=n;i++) cin>>a[i];
sort(a.begin()+1,a.end());
l=1,r=INF;
while(l<=r){
if(check(mid)){
res=mid;
r=mid-1;
}
else{
l=mid+1;
}
}
cout<<res<<endl;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
#ifndef ONLINE_JUDGE
input.open("D:\\UROS\\Programiranje\\input.in",ios::in);
output.open("D:\\UROS\\Programiranje\\output.out",ios::out|ios::trunc);
#endif
//freopen(".in","r",stdin);
//freopen(".out","w",stdout);
int t;
//cin>>t;
t=1;
while(t--){
solve();
}
return 0;
}
