#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
using namespace std;
vector<vector<int> > dp(2005, vector<int>(2005, 1e9));
int main() {
int n, p, q;
cin >> n >> p >> q;
p = min(n, p);
q = min(n, q);
vector<int> v(n+1, -1e9);
for(int i=1; i<=n; i++) cin >> v[i];
sort(1+all(v));
auto f = [&](int mid) {
for(int i=0; i<=n; i++)
for(int j=0; j<=p; j++) dp[i][j] = 1e9;
dp[0][0] = 0;
int k=0, l=0;
for(int i=1; i<=n; i++) {
while(v[i] - v[k] >= mid) k++;
while(v[i] - v[l] >= 2ll * mid) l++;
for(int j=0; j<=p; j++) {
if(j) dp[i][j] = dp[k-1][j-1];
dp[i][j] = min(dp[i][j], dp[l-1][j] + 1);
}
}
for(int i=0; i<=p; i++)
if(dp[n][i] <= q) return 1;
return 0;
};
int l=1, r=1e9, ans = 1e9;
while(l <= r) {
int mid = (l + r) / 2;
if(f(mid)) ans = mid, r = mid - 1;
else l = mid + 1;
}
cout << ans << '\n';
return 0;
}
