#include<cstdio>#define min(a,b) ((a)<(b)?(a):(b))#define inf 1<<30int main(){int n,m,i,j,t,ans,a,low[105],high[105],d[105];while(scanf("%d%d",&n,&m)==2){scanf("%d",&a);for(i=1;i<=100;i++)d[i]=i<a?inf:(a-i)*(a-i);for(i=1;i<n;i++){scanf("%d",&a);for(t=inf,j=100;j>0;j--)low[j]=t=min(t,d[j]+j*m);for(t=inf,j=1;j<=100;j++){high[j]=t=min(t,d[j]-j*m);d[j]=inf;}for(j=a;j<=100;j++)d[j]=(j-a)*(j-a)+min(low[j]-j*m,high[j]+j*m);}for(ans=inf,i=1;i<=100;i++)ans=min(ans,d[i]);printf("%dn",ans);}}
