#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef long double ld;
const int INF = 1e9 + 7;
const int MOD = 1e9 + 7;
ll a[2001];
int dp[2001][2001];
int n, p, q;
bool can(ll v)
{
memset(dp, -1, sizeof(dp));
for(int i = 0; i <= p; i++)
{
for(int j = 0; j <= q; j++)
{
if(dp[i][j] == n-1) return true;
dp[i+1][j]=max(dp[i+1][j], int(upper_bound(a, a+n, a[dp[i][j]+1]+v-1) - a - 1));
dp[i][j+1] = max(dp[i][j+1], int(upper_bound(a,a+n,a[dp[i][j]+1]+2*v-1) - a - 1));
}
}
return false;
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> p >> q;
for(int i = 0; i < n; i++)
{
cin >> a[i];
}
sort(a, a + n);
ll ans = -1;
ll lo = 1; ll hi = ll(1e9);
ll mid;
while(lo <= hi)
{
mid = (lo+hi)>>1;
if(can(mid))
{
hi = mid - 1;
ans = mid;
}
else
{
lo = mid + 1;
}
}
cout << ans;
}
