#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], v[mxN], dp[mxN][mxN];
bool work(int w){
for(int i = 2; i <= n; i++){
v[i]=v[i-1]+a[i]-a[i-1];
for(int j = i; j; j--){
if(v[i]-v[j]+1<=w) P[i]=j-1;
if(v[i]-v[j]+1<=2*w) Q[i]=j-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); v[1]=a[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;
}
