#include "boxes.h"
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
typedef long long ll;
using namespace std;
//using namespace __gnu_pbds;
#define FOR(i, x, y) for(ll i=x; i<y; i++)
#define FORNEG(i, x, y) for(ll i=x; i>y; i--)
//#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>
#define fast() ios_base::sync_with_stdio(false);cin.tie(NULL)
ll dp1[10000001], dp2[10000001];
long long delivery(int N, int K, int L, int p[]) {
FOR(i,0,10000001) dp1[i] = 0, dp2[i] = 0;
ll pos = 0;
ll prev = 0;
ll sus = K+1;
FOR(i,0,N){
sus -= 1;
if (sus == 0){
sus = K;
prev += min(abs(pos-0), abs(pos-L));
pos = 0;
}
prev += min(abs(pos - p[i]), abs(L-abs(pos - p[i])));
pos = p[i];
dp1[i] = prev+min(abs(pos-0), abs(pos-L));
if (p[i] == 0) sus = K+1;
}
pos = L;
prev = 0;
sus = K+1;
FORNEG(i, N-1, -1){
sus -= 1;
if (sus == 0){
sus = K;
prev += min(abs(pos-0), abs(pos-L));
pos = L;
}
prev += min(abs(pos - p[i]), abs(L-abs(pos - p[i])));
pos = p[i];
dp2[i] = prev+min(abs(pos-0), abs(pos-L));
if (p[i] == 0) sus = K+1;
}
ll ans = dp2[0];
FOR(i,0,N){
ans = min(ans, dp1[i] + dp2[i+1]);
}
return ans;
}
