#include<bits/stdc++.h>
using namespace std;
#pragma optimize("unroll-loops,Ofast")
//#pragma target("tune=native,sse4")
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;
typedef pair<int, ll> pil;
typedef pair<ll, ll> pll;
#define f first
#define s second
#define mkpr make_pair
#define pque priority_queue
#define pb push_back
#define pf push_front
#define vec vector
#define pf push_front
#define Yes cout << "Yes\n";
#define YES cout << "YES\n";
#define No cout << "No\n";
#define NO cout << "NO\n";
#define em(x) (bool)(x).empty()
#define all(x) (x).begin(), (x).end()
#define tc int tc;cin >> tc; while(tc--)
#define cps CLOCKS_PER_SEC
const int N = 2000 + 5, P = 1e9 + 7;
int n, q, p, a[N], dp[N][N];
bool ch(int w) {
memset(dp, 63, sizeof dp);
dp[0][0] = 0;
int x = 1, y = 1;
for(int i = 1; i <= n; i++) {
while(a[x] + w <= a[i]) x++;
while(a[y] + w + w <= a[i]) y++;
//cout << i << ' ' << x << ' '<< y << '\n';
dp[i][0] = dp[x - 1][0] + 1;
for(int j = 1; j <= i; j++)
dp[i][j] = min(dp[x-1][j] + 1, dp[y-1][j - 1]);
}
for(int i = 0; i <= q; i++)
if(dp[n][i] <= p)
return 1;
return 0;
}
int main() {
ios:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
cin >> n >> p >> q;
if (p + q >= n)
return cout << 1, 0;
for(int i = 1; i <= n; i++)
cin >> a[i];
sort(a+1, a + n+1);
//cout << ch(3) << '\n';
int l = 0, r = P;
while(r - l > 1) {
int mi = l + r >> 1;
if(ch(mi))
r = mi;
else
l = mi;
}
cout << r;
}
