#include <bits/stdc++.h>
using namespace std;
#define TL ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define rall(s) s.rbegin(),s.rend()
#define all(s) s.begin(),s.end()
#define pb push_back
#define se second
#define fi first
#define ll long long
#define ld long double
#define YES cout<<"YES\n"
#define Yes cout<<"Yes\n"
#define yes cout<<"yes\n"
#define NO cout<<"NO\n"
#define No cout<<"No\n"
#define no cout<<"no\n"
const int N = 1e7 + 9 , mod = 1e9 + 7;
ll b[N] , c[N] ;
ll delivery(int n,int k, int l,int a[])
{
for(int i = 1; i <= n; i++){
b[i] = min(l , a[i - 1] * 2);
if(i > k)
b[i] += b[i - k];
}
ll ans =b[n];
for(int i = n; i >= 1; i--){
c[i] = min(l , (l - a[i - 1]) * 2);
if(i + k <= n)
c[i] += c[i + k];
ans= min(ans , b[i - 1] + c[i]);
}
return ans;
}
// Author : حسن
