#include<stdio.h>
int main()
{
 char a,b;
 printf("Enter Two Characters\n");
 scanf("%c %c",&a,&b);
 int diff = (a - b);
 if(a==b)
    printf("Invalid Input\n");
 else if(diff>=0)
    printf("%d\n",diff-1);
 else
    printf("%d\n",-diff-1);
 return 0;
}