#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e7 + 3;
const long long inf = 1e16;
long long val1[maxn], val2[maxn];
long long best1[maxn], best2[maxn];
long long pr[maxn];
long long delivery(int n, int k, int l, int positions[])
{
vector <int> v1, v2;
for (int i = 0; i < n; i++)
{
if (positions[i] <= l / 2)
v1.push_back(positions[i]);
else
v2.push_back(positions[i]);
}
reverse(v2.begin(), v2.end());
int sz1 = (int)v1.size(), sz2 = (int)v2.size();
for (int i = 0; i < sz1; i++)
val1[i] = 2 * v1[i] + (i < k ? 0 : val1[i-k]);
for (int i = 0; i < sz2; i++)
val2[i] = 2 * (l - v2[i]) + (i < k ? 0 : val2[i-k]);
for (int i = 0; i < k; i++)
best1[i] = best2[i] = inf;
best1[sz1 % k] = min(best1[sz1 % k], 1ll * sz1 / k * l);
for (int i = 0; i < sz1; i++)
{
int left = sz1 - i - 1;
best1[left % k] = min(best1[left % k], val1[i] + 1ll * left / k * l);
}
best2[sz2 % k] = min(best2[sz2 % k], 1ll * sz2 / k * l);
for (int i = 0; i < sz2; i++)
{
int left = sz2 - i - 1;
best2[left % k] = min(best2[left % k], val2[i] + 1ll * left / k * l);
}
pr[0] = best2[0];
for (int i = 1; i < k; i++)
pr[i] = min(pr[i-1], best2[i]);
long long ans = inf;
for (int i = 0; i < k; i++)
{
if (i == 0)
ans = min(ans, best1[i] + best2[0]);
ans = min(ans, best1[i] + pr[min(k-1, k-i)] + l);
ans = min(ans, best1[i] + pr[k-1] + 2 * l);
}
return ans;
}
/*
int n, k, l, positions[maxn];
int main()
{
cin >> n >> k >> l;
for (int i = 0; i < n; i++)
cin >> positions[i];
cout << delivery(n, k, l, positions) << endl;
}
*/
