#include<bits/stdc++.h>
using namespace std;

int main(){
	int n, k;
	cin >> n >> k;
	
	long long d, h;
	d = (long long)-1e12 - 5;
	h = 1e6;
	
	int x[n];
	long long sum;
	map<long long, long long> res;
	
	for(int i = 0; i<n; i++){
		cin >> x[i];
	}
	
	sort(x, x + n);
	
	while(h -  d>= 5){
		long long mid1 = (d + h) / 2;
		long long mid2 = (h + d) / 2 + 1;
		
		long long cur = mid1;
		sum = 0;
		for(int j = 0; j<n; j++){
			sum += abs(x[j] - cur);
			cur += k;
		}
		
		res[mid1] = sum;
		
		cur = mid2;
		sum = 0;
		for(int j = 0; j<n; j++){
			sum += abs(x[j] - cur);
			cur += k;
		}
		
		res[mid2] = sum;
		
		if(res[mid1] < res[mid2]) h = mid2;
		else d = mid1;
	}
	
	long long mi = 1e9 * (long long)1e9;
	cout << mi << endl;
	for(int i = d - 2; i<= h + 2; i++){
		long long cur = i;
		sum = 0;
		for(int j = 0; j<n; j++){
			sum += abs(x[j] - cur);
			cur += k;
		}
		//cout << mi << endl;
		mi = min(sum, mi);
	}
	//cout << d << "  " << h << endl;
	cout << mi << endl;
}