using System;

namespace StringDistance
{
    class Program
    {
        static void Main(string[] args)
        {
			Func<string,int>f= s=>{int l=0,d,i=0;for(;i<s.Length-1;)l+=(d=Math.Abs(s[i]-s[++i]))>13?26-d:d;return l;};
			
			Console.WriteLine(f("golf"));	//17
			Console.WriteLine(f("aa"));		//0
			Console.WriteLine(f("stack"));	//18
			Console.WriteLine(f("zaza"));	//3
			Console.WriteLine(f("valleys"));//35
        }
    }
}