#include <bits/stdc++.h>
using namespace std;
const int mxn = 2e3+5;
typedef long long ll;
const ll inf = 1e16;
ll arr[mxn];
ll dp[mxn][mxn];
ll n, P, Q;
bool solve(ll w)
{
for(int i = 0; i <= n; i++)
for(int r = 0; r <= n; r++) dp[i][r] = inf;
dp[0][0] = 0;
for(int i = 1; i <= n; i++)
{
for(int r = 0; r <= P; r++)
{
int x = upper_bound(arr+1, arr+n+1, arr[i]-w)-arr-1;
int y = upper_bound(arr+1, arr+n+1, arr[i]-w-w)-arr-1;
if(r) dp[i][r] = min(dp[i][r], dp[x][r-1]);
dp[i][r] = min(dp[i][r], dp[y][r]+1);
}
}
for(int i = 0; i <= n; i++)
if(dp[n][i]<=Q) return true;
return false;
}
int main()
{
cin >> n >> P >> Q;
P = min(n, P);
Q = min(n, Q);
for(int i = 1; i <= n; i++) cin >> arr[i];
sort(arr+1, arr+n+1);
ll lo = 1, hi = 1e9+5, ans = inf;
while(lo<=hi)
{
ll mid = (lo+hi)>>1;
if(solve(mid))
{
hi = mid-1;
ans = min(ans, mid);
}
else lo = mid+1;
}
cout << ans << '\n';
return 0;
}
