fn getline() -> String{
        let mut __ret=String::new();
        std::io::stdin().read_line(&mut __ret).ok();
        return __ret;
}

fn main(){
        let astring = getline();
        let bstring = getline();
        let a:i64 = astring.trim().parse().unwrap_or(-1);
        let b:i64 = bstring.trim().parse().unwrap_or(-1);
        if a==-1 || b == -1 {
                println!("NG");
                return;
        }
        if astring.trim() != a.to_string().trim() || bstring.trim() != b.to_string().trim() {
                println!("NG");
                return;
        }
        if !(0 <= a && a <= 12345 && 0 <= b && b <= 12345) {
                println!("NG");
                return;
        }
        println!("OK");
}