import java.util.*;
import java.util.regex.*;
public class Main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        while(scan.hasNext()){
            String str = scan.nextLine();
            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");
        }
        scan.close();
    }
    public static boolean getMatch(String str){
        int count = 0;
        Pattern p1 = Pattern.compile("[0-9]");
        if(p1.matcher(str).find()){
            count++;
        }
        Pattern p2 = Pattern.compile("[a-z]");
        if(p2.matcher(str).find()){
            count++;
        }
        Pattern p3 = Pattern.compile("[A-Z]");
        if(p3.matcher(str).find()){
            count++;
        }
        Pattern p4 = Pattern.compile("[^0-9a-zA-Z]");
        if(p4.matcher(str).find()){
            count++;
        }
        if(count>=3){
            return false;
        }
        else{
            return true;
        }
    }
    
    public 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);
        }
    }
}