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);
}
}
}