How to find the distance between two letters. Java program

import java.util.Scanner;
public class Main
{
  public static void main(String[] args) throws Exception
  {
    Scanner in = new Scanner(System.in);
    char a = in.next().charAt(0);
    char b = in.next().charAt(0);
    a = Character.toLowerCase(a);
    b = Character.toLowerCase(b);
    int d1, d2;

    if ( a <= b )
    {
      d1 = b - a; // direct distance
      d2 = 26 - b + a; // distance considering wrap around
    }
    else
    {
      d1 = a - b; // direct distance
      d2 = 26 - a + b; // distance considering wrap around
    }
    int  d; // now the distance is the smallest between 'direct' and 'wrapped around'
    if ( d1 <= d2)
      d = d1;
    else
      d = d2;

    System.out.println(d);
  }
}