// In the name of Allah
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef complex<ld> cld;
#define all(x) (x).begin(),(x).end()
#define len(x) ((ll) (x).size())
#define F first
#define S second
#define pb push_back
#define sep ' '
#define endl '\n'
#define Mp make_pair
#define kill(x) cout << x << '\n', exit(0)
#define set_dec(x) cout << fixed << setprecision(x);
#define file_io(x,y) freopen(x, "r", stdin); freopen(y, "w", stdout);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxn = 1000 + 4;
int n, k; ll t;
ll A[maxn]; bool dp[maxn][maxn];
ll get_val(int i, int j, ll tx) {
return (tx * (j - i + 1)) - (A[j] - A[i]);
}
bool ok(ll x) {
ll tx = (t * x);
if (tx >= A[n - 1]) return 1;
for (int i = k; i >= 0; i--) {
for (int j = k; j < n; j++) {
if (i == k && j == k) {
dp[i][j] = 1;
}
else {
dp[i][j] = 0;
if (i + 1 <= k) {
if (get_val(i + 1, j, tx) >= (A[i + 1] - A[i])) dp[i][j] = 1;
}
if (j - 1 >= k) {
if (get_val(i, j - 1, tx) >= (A[j] - A[j - 1])) dp[i][j] = 1;
}
}
}
}
return dp[0][n - 1];
}
void solve() {
cin >> n >> k >> t; k--; t *= 2;
for (int i = 0; i < n; i++) {
cin >> A[i];
}
ll l = -1, r = (A[n - 1] / t) + 2;
while (r - l > 1) {
ll mid = (l + r) / 2;
if (ok(mid)) r = mid;
else l = mid;
}
cout << r << endl;
}
int main() {
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int T = 1;
while (T--) {
solve();
}
return 0;
}
