http://zerojudge.tw/ShowProblem?problemid=b204
#include<iostream>
using namespace std;
int main() {
int n,a,before,sum;
while (cin >> n){
if (n==0) break;
sum=0;
cin >> before;
for(int i=1;i<n;i++){
cin >> a;
if ( ){
sum+=(a-before)*20;
}else{
sum+=(before-a)*10;
}
before=a;
}
cout << sum << endl;
}
}