HDU 1008 Elevator

#include <iostream>
using namespace std;
int main()
{
	int a[233],i,j,k,sum;
	while(cin>>i,i){
		for(j=1;j<=i;j++) cin>>a[j];
		sum=k=0;
		for(j=1;j<=i;j++){
			if(a[j]-k>0) sum=sum+(a[j]-k)*6;
			if(a[j]-k<0) sum=sum+(k-a[j])*4;
			sum+=5;
			k=a[j];
		}
		cout<<sum<<endl;
	} 
	return 0;
 }