#include <bits/stdc++.h>
#include "boxes.h"
using namespace std;
#define fi first
#define se second
#define _size(x) (int)x.size()
#define BIT(i, x) ((x >> i) & 1)
#define MASK(n) ((1 << n) - 1)
#define REP(i, n) for (int i = 0, _n = (n); i < _n; i++)
#define FOR(i, a, b) for (int i = a, _b = (b); i <= _b; i++)
#define FORD(i, a, b) for (int i = a, _b = (b); i >= _b; i--)
#define FORB1(i, mask) for (int i = mask; i > 0; i ^= i & - i)
#define FORB0(i, n, mask) for (int i = ((1 << n) - 1) ^ mask; i > 0; i ^= i & - i)
#define FORALL(i, a) for (auto i: a)
#define fastio ios_base::sync_with_stdio(0); cin.tie(0);
const long long inf = 1e18;
long long delivery(int n, int k, int l, int positions[]) {
vector<int> pos;
REP(i, n) if (positions[i]) pos.push_back(positions[i]);
if (!_size(pos)) return 0;
n = _size(pos);
vector<long long> f(n);
REP(i, n) f[i] = 1LL * pos[i] + 1LL * min(l - pos[i], pos[i]) + (i < k ? 0 : f[i - k]);
vector<long long> g(n);
FORD(i, n - 1, 0) g[i] = 1LL * (l - pos[i]) + 1LL * min(l - pos[i], pos[i]) + (i + k > n - 1 ? 0 : g[i + k]);
long long ans = inf;
REP(i, n) {
ans = min(ans, f[i] + (i + 1 > n - 1 ? 0 : g[i + 1]));
ans = min(ans, f[i] + 1LL * l + (i + k > n - 1 ? 0 : g[i + k + 1]));
}
ans = min(ans, g[0]);
return ans;
}
