//雪花飄飄北風嘯嘯
//天地一片蒼茫
#include "boxes.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ii,ll>
#define fi first
#define se second
#define endl '\n'
#define debug(x) cout << #x << " is " << x << endl
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define lb lower_bound
#define ub upper_bound
#define rep(x,start,end) for(auto x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()
#define indexed_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
//change less to less_equal for non distinct pbds, but erase will bug
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
int n,k,l;
vector<int> f;
vector<int> b;
vector<ll> fa;
vector<ll> ba;
long long delivery(int N, int K, int L, int P[]) {
n=N,k=K,l=L;
rep(x,0,n) if (P[x]){
f.pub(P[x]);
b.pub(l-P[x]);
}
reverse(all(b));
n=sz(f);
fa.pub(0);
rep(x,0,n){
if (x<k) fa.pub(f[x]);
else fa.pub(fa[x-k+1]+f[x]);
}
ba.pub(0);
rep(x,0,n){
if (x<k) ba.pub(b[x]);
else ba.pub(ba[x-k+1]+b[x]);
}
//for (auto &it:fa) cout<<it<<" "; cout<<endl;
ll ans=1e18;
rep(x,0,n+1){
ans=min(ans,(fa[x]+ba[n-x])*2);
}
//cout<<ans<<endl;
rep(x,0,n+1){
int other=n-x-k;
if (other<0) continue;
ans=min(ans,(fa[x]+ba[other])*2+l);
}
if (n<=k) ans=min(ans,(ll)l);
return ans;
}
