#include <bits/stdc++.h>
using namespace std;
const int N = 2005, INF = 1e9 + 7;
int n, X, Y, r, a[N], dp[N][N], ans;
bool check(int w){
for (int i = 0; i <= n; ++i)
for (int j = 0; j <= X; ++j) dp[i][j] = INF;
dp[0][0] = 0;
int u = 1, v = 1;
for (int i = 1; i <= n; ++i){
while (a[i] - a[u] + 1 > w)
++u;
while (a[i] - a[v] + 1 > (w << 1))
++v;
for (int j = 0; j <= X; ++j){
//cerr << j << "\n";
if (j)
dp[i][j] = min(dp[i][j], dp[u - 1][j - 1]);
dp[i][j] = min(dp[i][j], dp[v - 1][j] + 1);
// if (w == 3){
// cout << "\t" << i << " " << j << "\t" << u - 1 << " " << j - 1 << " " << dp[u - 1][j - 1] << "\t" << v - 1 << " " << j << " " << dp[v - 1][j] + 1 << "\n";
// }
}
}
// if (w == 3)
// for (int i = 0; i <= X; ++i) cout << i << "\t" << dp[n][i] << "\n";
for (int i = 0; i <= X; ++i)
if (dp[n][i] <= Y) return 1;
return 0;
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> X >> Y;
X = min(X, n);
for (int i = 1; i <= n; ++i) cin >> a[i], r = max(r, a[i]);
sort(a + 1, a + n + 1);
int l = 1;
while (l <= r){
int mid = l + ((r - l) >> 1);
//cerr << l << " " << r << "\n";
if (check(mid)){
ans = mid;
r = mid - 1;
} else
l = mid + 1;
}
cout << ans;
}
