#include <bits/stdc++.h>
#include "boxes.h"
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
using namespace std;
int dist(int x,int y,int L){
if(x>y)swap(x,y);
return min(y-x,L-y+x);
}
long long delivery(int N, int K, int L, int p[]) {
map <int,int> mp;
for(int i=0;i<N;i++){
mp[p[i]]++;
}
set <int> st;
for(auto x : mp){
st.insert(x.ff);
}
int cur=0,pres=K;
long long ans=0;
while(!st.empty()){
auto it=st.upper_bound(cur);
int next=-1,mn=1e9;
if(it!=st.end()){
if(dist(cur,*it,L)<mn){
mn=dist(cur,*it,L);
next=*it;
}
}
if(it!=st.begin()){
it--;
if(dist(cur,*it,L)<mn){
mn=dist(cur,*it,L);
next=*it;
}
}
ans+=(long long)mn;
cur=next;
int x=mp[cur];
mp[cur]-=min(x,pres);
pres-=min(x,pres);
if(mp[cur]==0)st.erase(cur);
if(pres==0){
pres=K;
ans+=(long long)dist(cur,0,L);
cur=0;
}
}
ans+=(long long)dist(cur,0,L);
return ans;
}
/*
signed main(){
ios_base::sync_with_stdio();
cin.tie(0);cout.tie(0);
int n,k,l;
cin>>n>>k>>l;
int pos[n];
for(int i=0;i<n;i++)cin>>pos[i];
cout<<delivery(n,k,l,pos);
}
*/
