#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ar array
const int mxN = 2005, M = 1e9+7;
int n, p, q, a[mxN];
int nxt1[mxN], nxt2[mxN];
int dp[mxN][mxN];
bool trial(int pos){
for(int i = 0; i<n; ++i){
nxt1[i] = (int)(lower_bound(a, a+n, a[i]+pos)-a);
nxt2[i] = (int)(lower_bound(a, a+n, a[i]+2*pos)-a);
}
nxt1[n] = nxt2[n] = n;
for(int i = p; i>=0; --i){
for(int j = q; j>=0; --j){
if(i == p && j == p) continue;
int ans = 0;
if(i != p){
ans = max(ans, nxt1[dp[i+1][j]]);
}
if(j != q){
ans = max(ans, nxt2[dp[i][j+1]]);
}
dp[i][j] = ans;
}
}
return dp[0][0] >= n;
}
int main(){
#ifdef _DEBUG
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
#endif
std::ios_base::sync_with_stdio(false); std::cin.tie(0); std::cout.tie(0);
cin >> n >> p >> q;
for(int i = 0; i<n; ++i){
cin >> a[i];
}
p = min(p, n);
q = min(q, n);
sort(a, a+n);
int l = 0, r = 1e9;
while(l<r){
int mid = (l+r)/2;
if(trial(mid)) r = mid;
else l = mid+1;
}
cout << l << "\n";
}
