#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define mp make_pair
typedef pair<int,int> ii;
long long l,r,n,p,q,dp[2005][2005],nxt[2005][3],a[2005];
vector<long long> vec;
bool check(long long w){
a[n+1] = a[n];
for(int i = 0;i<=n+1;i++){
for(int j = 0;j<=1;j++){
long long cost;
if(j == 0)
cost = w-1;
else
cost = 2*w-1;
int it = upper_bound(vec.begin(),vec.end(),a[i]+cost) - vec.begin() - 1;
nxt[i][j] = it;
}
}
memset(dp,0,sizeof(dp));
for(int i = 0;i<=p;i++){
for(int j = 0;j<=q;j++){
if(i>=1)
dp[i][j] = nxt[dp[i-1][j]+1][0];
if(j>=1)
dp[i][j] = max(dp[i][j],nxt[dp[i][j-1]+1][1]);
}
}
if(dp[p][q]>=n)
return 1;
else
return 0;
}
int main(){
cin.tie(0),ios::sync_with_stdio(0);
cin >> n >> p >> q;
for(int i = 1;i<=n;i++){
cin>>a[i];
vec.pb(a[i]);
}
sort(a+1,a+1+n);
vec.pb(-1);
sort(vec.begin(),vec.end());
if(p+q>=n){
cout<<"1\n";
return 0;
}
l = 1;
r = 1e9;
while(l<r){
long long mid = (l+r)/2;
if(check(mid))
r = mid;
else
l = mid+1;
}
cout<<l;
}
