check if input contains all letters of alphabet (case in-sensitive)

PangramCheck.java

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class PangramCheck {
    public static void main(String args[] ) throws Exception {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT */
        // Output "pangram" or "not pangram" depending if input sentence contains
        // all the letters of the English alphabet or not

        HashSet<Character> set = new HashSet<Character>();  
        
        Scanner in = new Scanner(System.in);
        in.useDelimiter("");  // make scanner give strings of length==1
        
        while (in.hasNext()) {
            char c = in.next().charAt(0); // returns primitive     
            if (Character.isLetter(c)) set.add(Character.toLowerCase(c));
        }
        String result;
        result = (set.size() == 26) ? "pangram" : "not pangram";
        System.out.println(result);
    }
}