/**
_ _ __ _ _ _ _ _ _
|a ||t ||o d | |o |
| __ _| | _ | __| _ |
| __ |/_ | __ /__\ / _\|
**/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int N_MAX = 1000;
int N, K, T;
int X[N_MAX + 2];
bool dp[N_MAX + 2][N_MAX + 2];
bool check (int speed) {
dp[1][N] = true;
for (int l = 1; l <= K; l++) {
for (int r = N - (l == 1); r >= K; r--) {
dp[l][r] = false;
if (l > 1 && X[r] - X[l - 1] <= (ll) speed * (r - l + 1) * 2 * T) {
dp[l][r] |= dp[l - 1][r];
}
if (r < N && X[r + 1] - X[l] <= (ll) speed * (r - l + 1) * 2 * T) {
dp[l][r] |= dp[l][r + 1];
}
}
}
return dp[K][K];
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> N >> K >> T;
for (int i = 1; i <= N; i++) {
cin >> X[i];
}
int l = 0, r = (int) 1e9 / T + 1;
while (l < r) {
int mid = (l + r) / 2;
if (check(mid) == true) {
r = mid;
} else {
l = mid + 1;
}
}
cout << l << "\n";
return 0;
}
