#include <iostream>

 #include <cstdio>

 using namespace std;

 int main()

 {

     int i, n, m, time;

     int floors[] = {};

     while(cin>>n && n) {

         time = ;

         cin >> floors[];

         time += floors[]* + ;

         for(i=; i<n; i++) {

             cin >> floors[i];

             m = floors[i] - floors[i-];

             if(m > ) {

                 time += m* + ;

             }else{

                 time += (-m)* + ;

             }

         }

         cout << time << endl;

     }

     return ;

 }