java

import java.util.*;
import java.util.regex.*;
public class Main{
    public static void main(String[] arg){
        Scanner sc=new Scanner(System.in);
        while(sc.hasNext()){
            String str=sc.next();
            if(str.length()<=8){
                System.out.println("NG");
                continue;
            }

            if(getMatch(str)){
                System.out.println("NG");
                continue;
            }

            if(getString(str,0,3)){
                System.out.println("NG");
                continue;
            }
            System.out.println("OK");
        }
    }
        private static boolean getString(String str,int l,int r) {
        if (r>=str.length()) {
            return false;
        }
        if (str.substring(r).contains(str.substring(l, r))) {
            return true;
        } else {
            return getString(str,l+1,r+1);
        }
    }

    private static boolean getMatch(String str){
        int count=0;
        Pattern p1 = Pattern.compile("[A-Z]");
         if(p1.matcher(str).find()){
            count++;
        }
        Pattern p2 = Pattern.compile("[a-z]");
        if(p2.matcher(str).find()){
            count++;
        }
        Pattern p3 = Pattern.compile("[0-9]");
        if(p3.matcher(str).find()){
            count++;
        }
        Pattern p4 = Pattern.compile("[^a-zA-Z0-9]");
        if(p4.matcher(str).find()){
            count++;
        }
        if(count>=3){
            return false;
        }else{
            return true;
        }
    }
}