HDU--1008--Elevator

#include <stdio.h>int main (void){    int n,a,s,i;    while(scanf("%d",&n)!=EOF)    {        s=0,i=0;        if(!n)        break;        while(n--)        {            scanf("%d",&a);            if(a>i)            s+=6*(a-i)+5,i=a;            else            if(a==i)            s+=5;            else            s+=4*(i-a)+5,i=a;        }        printf("%d\n",s);    }    return 0;}