#include <bits/stdc++.h>
using namespace std;
int n, p, q;
int a[2001];
vector<vector<int>> dp;
bool moze(int w){
dp.assign(q+1, vector<int>(p+1));
dp[0][0] = 0;
for(int bg = 0; bg <= q; bg++){
for(int sm = 0; sm <= p; sm++){
if(sm != 0) {
int sx = a[dp[bg][sm-1] + 1] + w;
sx = lower_bound(a+1, a+1+n, sx) - a - 1;
dp[bg][sm] = max(dp[bg][sm], sx);
}
if(bg != 0){
int bx = a[dp[bg-1][sm] + 1] + 2*w;
bx = lower_bound(a+1, a+1+n, bx) - a - 1;
dp[bg][sm] = max(dp[bg][sm], bx);
}
if(dp[bg][sm] == n) return true;
}
}
return false;
}
signed main(){
//ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> p >> q;
for(int i = 1; i <= n; i++) cin>>a[i];
p = min(p, n);
q = min(q, n);
sort(a+1, a + n+1);
int l = 1, r = 1e9;
while(l < r){
int m = (l+r)>>1;
if(moze(m)){
r = m;
}
else {
l = m+1;
}
}
cout << r << '\n';
return 0;
}
