use std::io;
use std::str::FromStr;

fn main() {
    let stdin = io::stdin();
    let mut buf = String::new();
    stdin.read_line(&mut buf).ok();

    let mut it = buf.split_whitespace().map(|n| String::from_str(n).unwrap());
    let a = it.next().unwrap();

    let mut buf = String::new();
    stdin.read_line(&mut buf).ok();

    let mut it = buf.split_whitespace().map(|n| String::from_str(n).unwrap());
    let b = it.next().unwrap();

    if a.chars().nth(0) == Some('0') && a.len() != 1 {
        println!("NG");
        return;
    }
    // println!("{}", b);
    // println!("{:?}", b.chars().nth(0));

    if b.chars().nth(0) == Some('0') && b.len() != 1 {
        println!("NG");
        return;
    }

    let aa = a.parse::<i64>().is_ok();
    let bb = b.parse::<i64>().is_ok();
    if aa && bb {

        if a.parse::<i32>().unwrap() > 12345 {
            println!("NG");
            return;
        }
        if b.parse::<i32>().unwrap() > 12345 {
            println!("NG");
            return;
        }

        println!("OK");
    } else {
        println!("NG");
    }

}