#include<bits/stdc++.h>
using namespace std;

int main()
{
    char first[2], second[2];

    cin>>first>>second;

    int i,count=0;

    i= strlen(first);

    for(int n=0; n<i; n++)
    {

        if(first[n]!=second[n])
        {
            if(first[n]!=second[n]+32||first[n]!=second[n]-32)
            {
                if(first[n]<91 && second[n]<91)
                {
                    count=count+first[n]-second[n];
                }
                else if(first[n]>96 && second[n]>96)
                {
                    count=count+first[n]-second[n];
                }
                else if (first[n]>96 && second[n]<91)
                {
                    second[n]=second[n]+32;
                    count=count+first[n]-second[n];
                }
                else if (first[n]<91 && second[n]>96)
                {
                    first[n]=first[n]+32;
                    count=count+first[n]-second[n];
                }


            }
        }
    }
    cout<<count;
}