#include<bits/stdc++.h>
using namespace std;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int n,p,q;cin>>n>>p>>q;
vector<int>arr(n);
for (int i = 0;i<n;++i)cin>>arr[i];
sort(arr.begin(),arr.end());
int left = 1,right = 1e9;
int ans = right;
function<bool(int)>check = [&](int u){
int cur = 0;
int sum = arr[0];
int big = q,small = p;
while(cur < n){
int nxt = lower_bound(arr.begin(),arr.end(),sum + 2 * u - 1) - arr.begin();
int nxt2 = lower_bound(arr.begin(),arr.end(),sum + u - 1) - arr.begin();
while(nxt!=n && arr[nxt] - sum > 2 * u - 1)--nxt;
while(nxt2!=n && arr[nxt2] - sum > u - 1)--nxt2;
while(nxt + 1<n && arr[nxt + 1] - sum <=2 * u - 1)++nxt;
while(nxt2 + 1<n && arr[nxt2 + 1] - sum <=u - 1)++nxt2;
if (nxt - cur >= 1 && (nxt - cur + 1) >= 2 * (nxt2 - cur + 1) && big){
--big;
cur = nxt + 1;
sum = arr[cur];
}
else if (nxt2 - cur >= 1 && small){
--small;
cur = nxt2 + 1;
sum = arr[cur];
}
else if (nxt - cur >= 1 && big){
--big;
cur = nxt + 1;
sum = arr[cur];
}
else if (small){
cur = cur + 1;
small--;
sum = arr[cur];
}
else if (big){
cur = cur + 1;
big--;
sum = arr[cur];
}
else break;
}
return (cur >= n);
};
while(left<=right){
int mid = (left + right)>>1;
if (check(mid)){
right = mid - 1;
ans = mid;
}
else{
left = mid + 1;
}
}
cout<<ans<<'\n';
return 0;
}
