/*input
3 2 8
1 2 5
*/
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define int ll
#define pb push_back
#define INF 1000000000
#define MOD 1000000007
#define mp make_pair
const double PI=3.141592653589793238462643383279502884197169399375105820974944;
#define REP(i,n) for (int i = 0; i < n; i++)
#define FOR(i,a,b) for (int i = a; i < b; i++)
#define REPD(i,n) for (int i = n-1; i >= 0; i--)
#define FORD(i,a,b) for (int i = a; i >= b; i--)
#define remax(a,b) a = max(a,b)
#define remin(a,b) a = min(a,b)
#define all(v) v.begin(),v.end()
#define pii pair<int,int>
#define F first
#define S second
#define mii map<int,int>
#define vi vector<int>
#define vvi vector<vi>
#define itr :: iterator it
#define WL(t) while(t --)
#define gcd(a,b) __gcd((a),(b))
#define lcm(a,b) ((a)*(b))/gcd((a),(b))
#define print(arr) for (auto it = arr.begin(); it != arr.end(); ++it) cout << *it << " "; cout << endl;
#define debug(x) cout << x << endl;
#define debug2(x,y) cout << x << " " << y << endl;
#define debug3(x,y,z) cout << x << " " << y << " " << z << endl;
int power(int a,int b,int m = MOD){
if(b == 0) return 1;
if(b == 1) return a;
int x = power(a,b/2,m)%m;
x = (x*x)%m;
if(b%2) return (x*a)%m;
return x;
}
int n,k,l,a[(ll)1e7+5],cw[(ll)1e7+5],acw[(ll)1e7+5];
int delivery(signed N, signed K, signed L, signed p[]){
n = N;
k = K;
l = L;
FOR(i,1,n+1) a[i] = p[i-1];
cw[0] = 0;
FOR(i,1,n+1){
if(i <= k) cw[i] = 2*a[i];
else cw[i] = 2*a[i]+cw[i-k];
}
acw[n+1] = 0;
for(int i = n; i > 0; i --){
if(i+k > n) acw[i] = abs(l-a[i])*2;
else acw[i] = abs(l-a[i])*2+acw[i+k];
}
int ans = cw[n];
REP(i,n+1){
// cout << i << " " << cw[i] << endl;
remin(ans,cw[i]+acw[i+1]);
if(i+k <= n) remin(ans,cw[i]+l+acw[i+k+1]);
else remin(ans,cw[i]+l);
}
return ans;
}
