#include <bits/stdc++.h>
/// #pragma GCC optimize ("Ofast")
/// #pragma GCC target ("avx2")
/// #pragma GCC optimize("unroll-loops")
using namespace std;
using ll = long long;
using ii = pair<ll, ll>;
using vi = vector<int>;
#define ff first
#define ss second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lb lower_bound
#define int ll
const int MOD = 1000 * 1000 * 1000 + 7;
int N, P, Q, A[2001], DP[2001][2001];
int solve(int v) {
int X[N], Y[N];
for(int l = 0, i = 0; l < N; l++) {
while(A[l] - A[i] >= v) i++;
X[l] = i;
}
for(int l = 0, i = 0; l < N; l++) {
while(A[l] - A[i] >= 2 * v) i++;
Y[l] = i;
}
for(int l = 0; l <= N; l++)
for(int i = 0; i <= P; i++)
DP[l][i] = 1e9 + 7;
DP[0][0] = 0;
for(int l = 1; l <= N; l++) {
for(int i = 0; i <= P; i++) {
if(i > 0) DP[l][i] = min(DP[l][i], DP[X[l - 1]][i - 1]);
if(DP[Y[l - 1]][i - 1] != 1e9 + 7)
DP[l][i] = min(DP[l][i], DP[Y[l - 1]][i] + 1);
}
}
for(int l = 0; l <= P; l++)
if(DP[N][l] <= Q) return 1;
return 0;
}
int32_t main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> N >> P >> Q;
P = min(P, N), Q = min(Q, N);
for(int l = 0; l < N; l++) cin >> A[l];
sort(A, A + N);
int lo = 1, hi = 1e9, res = 1e9 + 7;
while(lo <= hi) {
int md = (lo + hi) / 2;
if(solve(md)) hi = md - 1, res = md;
else lo = md + 1;
}
cout << res << "\n";
return 0;
}
