#include <bits/stdc++.h>
using namespace std;
int N,P,Q,A[2005],sec1[2005],sec2[2005],dp[2005][2005];
bool check(int w){
for(int i = 0;i<N;++i){
sec1[i] = (int)(lower_bound(A,A+N,A[i]+w)-A);
sec2[i] = (int)(lower_bound(A,A+N,A[i]+2*w)-A);
}
sec1[N] = sec2[N] = N;
for(int i = P;i>=0;--i){
for(int j = Q;j>=0;--j){
if(i == P && j == Q) continue;
int cur = 0;
if(i != P) cur = max(cur,sec1[dp[i+1][j]]);
if(j != Q) cur = max(cur,sec2[dp[i][j+1]]);
dp[i][j] = cur;
}
}
return dp[0][0] >= N;
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> N >> P >> Q;
P = min(P,N); Q = min(Q,N);
for(int i = 0;i<N;++i) cin >> A[i];
sort(A,A+N);
int lo = 0, hi = 500000000;
while(lo < hi){
int mid = (lo+hi)/2;
if(check(mid)){
hi = mid;
}
else{
lo = mid+1;
}
}
cout << lo << "\n";
return 0;
}
