package com.pangrams;

import java.io.BufferedReader;

import java.io.FileReader;

import java.io.IOException;

public class Pangrams {

public static void main(String[] args) throws IOException {

BufferedReader buffer = new BufferedReader(new FileReader(args[0]));

String line = "";

while((line = buffer.readLine()) != null) {

System.out.println(pangram(line));

}

buffer.close();

}

private static String pangram(String line) {

String result = "";

String alphabets = "abcdefghijklmnopqrstuvwxyz";

int length = alphabets.length();

for (int counter = 0; counter < length; counter++) {

String alphabet = alphabets.charAt(counter) + "";

if (!line.contains(alphabet)) {

result += alphabet;

}

}

if(result.isEmpty()) {

return "NULL";

}

return result;

}

}