//~ #pragma GCC optimize("O3,unroll-loops")
//~ #pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define fi first
#define se second
#define pb push_back
#define endl "\n"
//~ #define int long long
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
const int inf = INT_MAX;
const int mod = 1e9+7;
int n, p, q;
int a[2005], dp[2005][2005];
bool check(int w){
for(int i=n;i>=1;i--){
int ind1 = upper_bound(a+1, a+n+1, a[i]+w-1) - a;
int ind2 = upper_bound(a+1, a+n+1, a[i]+2*w-1) - a;
for(int j=0;j<=p;j++){
int t1 = inf, t2 = inf;
if(j)t1 = dp[ind1][j-1];
t2 = dp[ind2][j]+1;
dp[i][j] = min(t1, t2);
}
}
if(dp[1][p]<=q)return true;
else return false;
}
int32_t main(){
fast;
cin>>n>>p>>q;
for(int i=1;i<=n;i++){
cin>>a[i];
}
sort(a+1, a+n+1);
if(p + q >= n){
cout<<1<<endl;
return 0;
}
int l = 1, r = 1e9;
while(l<=r){
int m = (l+r)/2;
if(check(m)){
r = m-1;
}
else l = m+1;
}
cout<<l<<endl;
}
