#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"
#define INF 1000000000
#define LINF 1000000000000000LL
#define pb push_back
#define all(x) x.begin(), x.end()
#define len(s) (int)s.size()
#define test_case { int t; cin>>t; while(t--)solve(); }
#define single_case solve();
#define line cerr<<"----------"<<endl;
#define ios { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cerr.tie(NULL); }
#define mod 1000000007LL
ll n, p, q;
const int N = 2005;
vector<ll> a;
ll dp[N][N];
int main()
{
ios
cin>>n>>p>>q;
a.pb(0);
for(int i = 1;i<=n;i++)
{
ll x;
cin>>x;
a.pb(x);
}
sort(all(a));
if(p+q>=n)
{
cout<<1;
return 0;
}
ll ans = 1e9;
ll l = 1;
ll r = 1e9;
while(l<=r)
{
ll mid = (r+l)/2;
//mid = 4;
for(int i = 0;i<=n;i++) for(int j = 0;j<=n;j++) dp[i][j] = INF;
for(int i = 0;i<=n;i++) dp[0][i] = 0;
for(int i = 1;i<=n;i++)
{
int w = a[i] - mid;
int ind = upper_bound(all(a), w) - a.begin();
if(ind)
{
ind--;
for(int j = 0;j<=n;j++)
{
dp[i][j] = dp[ind][j] + 1;
}
}
else
{
for(int j = 0;j<=n;j++)
{
dp[i][j] = 1;
if(j) dp[i][j] = 0;
}
}
ind = upper_bound(all(a), a[i] - 2*mid) - a.begin();
if(ind)
{
ind--;
for(int j = 1;j<=n;j++)
{
dp[i][j] = min(dp[i][j], dp[ind][j-1]);
}
}
else
{
for(int j = 1;j<=n;j++) dp[i][j] = 0;
}
}
bool moze = false;
for(int i = 0;i<=n;i++)
{
if(i<=q&&dp[n][i]<=p) moze = true;
}
/*for(int i = 1;i<=n;i++)
{
for(int j = 0;j<=n;j++)
cout<<dp[i][j]<<" ";
cout<<endl;
}*/
if(moze)
{
ans = mid;
r = mid - 1;
}
else
{
l = mid + 1;
}
//break;
}
cout<<ans;
return 0;
}
