#include<bits/stdc++.h>
#define ll long long 
#define dd double
#define ss string 
#define bb break;
#define ff for 
using namespace std; 
int main()
{
	ll ans=0;
	ss a;
	cin>>a;
	ff(ll i=0;i<a.size();i++)
	{
		if(a[i]>='A'&&a[i]<='Z') ans+=0;
		ll x=abs('A'-a[i]),y=abs('Z'-a[i]);
		if(x>y) ans+=abs('Z'-a[i]);
		else ans+=abs('A'-a[i]);
	}
	cout<<ans;
}