Steam Key

import java.util.*;
import java.lang.*;
import java.io.*;

class SteamKey
{
    public static void main (String[] args) throws java.lang.Exception
    {
        String keyout = "";
        int[] keycode = {8, 20, -2, -6, 2, -7, -2, -1, 6, -6, -3, 15, -7, -14, 27};
        int reg = 0;
        int c = 0;
        for(int d : keycode){
            if(c % 5 == 0 && c != 0){
                keyout = keyout + "-";
            }
            c++;
            reg += d;
            if(reg > 9){
                keyout = keyout + getCharForNumber(reg-10);
            }else{
                keyout = keyout + reg;
            }
        }
        System.out.println(keyout);

    }
    public static String getCharForNumber(int i) {
        return i > 0 && i < 27 ? String.valueOf((char)(i + 64)) : null;
    }
}