#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define sz(a) (int)a.size()
const int mxN = (int)2e3+10;
const int LINF = (int)1e9;
int n, p, q;
int a[mxN], P[mxN], Q[mxN], dp[mxN][mxN];
bool work(int w){
for(int i=2,j=1,k=1; i <= n; i++){
while(a[i]-a[j]+1>w) j++;
while(a[i]-a[k]+1>2*w) k++;
P[i]=j-1,Q[i]=k-1;
}
for(int i = 1; i <= n; i++){
for(int j = 0; j <= q; j++){
dp[i][j] = min(LINF, dp[P[i]][j]+1);
if(j) dp[i][j] = min(dp[i][j], dp[Q[i]][j-1]);
}
}
return dp[n][q]<=p;
}
int32_t main() {
ios_base::sync_with_stdio(false); cin.tie(0);
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;return 0;}
int l = 1, r = (int)1e9;
while(l<r){
int mid = (l+r)/2;
if(work(mid)) r=mid;
else l=mid+1;
}
cout << l;
}
