#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e3 + 5;
ll n, k, t;
ll x[N];
bool dp[N][N];
bool check(__int128 v) {
memset(dp, 0, sizeof(dp));
dp[1][n] = 1;
for (int l = 1; l <= k; ++l) {
for (int r = n; r >= k; --r) {
if (l == 1 && r == n) continue;
if (l > 1 && dp[l - 1][r] == 1 && x[r] - x[l - 1] <= 2 * v * (r - l + 1) * t) {
dp[l][r] = 1;
}
if (r < n && dp[l][r + 1] == 1 && x[r + 1] - x[l] <= 2 * v * (r - l + 1) * t) {
dp[l][r] = 1;
}
}
}
return dp[k][k];
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> k >> t;
for (int i = 1; i <= n; ++i) cin >> x[i];
ll l = 1, r = 1e9, sol = 0;
while (l <= r) {
ll m = (l + r) / 2;
if (check(m)) {
sol = m;
r = m - 1;
} else {
l = m + 1;
}
}
cout << sol << "\n";
return 0;
}
