#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <random>
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
	int n;
	ll p;
	cin>>n>>p;
	ll s1[200001], s2[200001];
	s1[0]=0, s2[0]=0;
	ll h[200001];
	ll dp[200001], mn1[200001], mn2[200001];
	for(int i=0; i<n; i++){
		cin>>h[i];
		if(i>0){
			s1[i]=s1[i-1]+max(h[i]-h[i-1], 0ll);
			s2[i]=s2[i-1]+max(h[i-1]-h[i], 0ll);
		}
	}
	dp[0]=0, mn1[0]=-s1[1], mn2[0]=-s2[1];
	for(int i=1; i<n; i++){
		dp[i]=s1[i];
		dp[i]=min(dp[i], mn1[i-1]+s1[i]+p);
		dp[i]=min(dp[i], mn2[i-1]+s2[i]+p);
		if(i<n-1){
			mn1[i]=min(mn1[i-1], dp[i]-s1[i+1]);
			mn2[i]=min(mn2[i-1], dp[i]-s2[i+1]);
		}
	}
	cout<<dp[n-1]<<endl;
	return 0;
}