#include <bits/stdc++.h>
using namespace std;
#define int long long
const int MAXN = 1e7+4;
int lpr[MAXN];
int rpr[MAXN];
int N, K, L;
int ans(int a, int b){
if (a>b) return 0;
return min(b + min(L-b, b), L-a + min(L-a, a));
}
int delivery(signed n, signed k, signed l, signed p[]){
N=n;K=k;L=l;
int r = n%k;
for (int i=0; i<n; i++){
if (i%k == k-1) lpr[i] += ans(p[i-k+1], p[i]);
if (i>0) lpr[i] += lpr[i-1];
}
for (int i=n-1; i>=0; i--){
if (i%k == n%k) rpr[i] += ans(p[i], p[i+k-1]);
if (i<n-1) rpr[i] += rpr[i+1];
}
int res = 1e18;
for (int i=0; i<n; i+=k){
res = min(res, (i?lpr[i-1]:0) + ans(p[i], p[i+r-1]) + rpr[i]);
}
return res;
}
