use strict;
use warnings;

my($a, $b) = (<>, <>);
my $ans = 'OK';

if($a > 12345 or $b > 12345){
    $ans = 'NG';
}
if($a =~ m/[^\d]/g or $b =~ m/[^\d]/g){
    $ans  = 'NG';
}
if($a =~ m/0\d/ or $b =~ m/0\d/){
    $ans = 'NG';
}

print $ans;