/*input
3 1 1
2
11
17
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<long long, null_type, less_equal<long long>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
#pragma GCC optimize("unroll-loops,no-stack-protector")
//order_of_key #of elements less than x
// find_by_order kth element
typedef long long int ll;
#define ld double
#define pii pair<ll,ll>
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
const ll maxn=2e3+5;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
const int INF=0x3f3f3f3f;
const ll MOD=ll(1e9+7);
const ld PI=acos(-1);
const ld eps=1e-9;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())
ll mult(ll a,ll b){
return (a*b)%MOD;
}
ll mypow(ll a,ll b){
if(b<=0) return 1;
ll res=1LL;
while(b){
if(b&1) res=mult(res,a);
a=mult(a,a);
b>>=1;
}
return res;
}
int n,p,q;
int arr[maxn];
int dp[maxn][maxn];
bool wk(int w){
FILL(dp,0);
int p1=0,p2=0;
REP(i,n){
REP(j,q+1){
if(i==0 and j==0){
dp[i][j]=1;
continue;
}
else if(i==0) dp[i][j]=0;
else{
while(arr[p1]<arr[i]-w+1) ++p1;
while(arr[p2]<arr[i]-2*w+1) ++p2;
dp[i][j]=INF;
if(p1>0){
dp[i][j]=dp[p1-1][j]+1;
}
else dp[i][j]=1;
if(j>0 and p2>0){
MNTO(dp[i][j],dp[p2-1][j-1]);
}
else if(p2==0 and j>0){
dp[i][j]=0;
//cout<<p1<<' '<<p2<<' '<<dp[i][j]<<' ';
}
}
}
//cout<<'\n';
}
if(dp[n-1][q]<=p) return true;
return false;
}
int main(){
cin>>n>>p>>q;
if(p+q>=n){
cout<<1;
return 0;
}
REP(i,n) cin>>arr[i];
sort(arr,arr+n);
ll l=2,r=2e9;
while(l<r){
//cout<<l<<' '<<r<<'\n';
int mid=(l+r)/2;
if(wk(mid)) r=mid;
else l=mid+1;
}
cout<<l;
}
