use std::cmp;

fn get_line() -> Vec<String> {
    let stdin = std::io::stdin();
    let mut s = String::new();
    loop {
        stdin.read_line(&mut s).ok();
        let s = s.trim();
        if s.len() != 0 {
            // println!("show: {}", s);
            return s.split_whitespace().map(|s| s.into()).collect();
        }
    }
}

fn main() {
    let ref a = get_line()[0];
    let ref b = get_line()[0];

    let ng = |s : &str| {
        if !s.chars().all(|c| c.is_digit(10)) {
            return true;
        }
        if s.len() != 1 && s.chars().nth(0) == Some('0') {
            return true;
        }
        return false;
    };

    if ng(&a) || ng(&b) {
        println!("NG");
        return;
    }

    let num_a : i32 = a.parse().unwrap();
    let num_b : i32 = b.parse().unwrap();
    if cmp::max(num_a, num_b) > 12345 {
        println!("NG");
    } else {
        println!("OK");
    }
}