#include<stdio.h>
#include<string.h>
int main()
{
	char str1[8], str2[8];
	scanf("%s%s", str1, str2);
	int i, len1, len2;
	len1 = strlen(str1);
	for (i = 0; i < len1; i++)
	{
		if (str1[i] < '0' || '9' < str1[i])
		{
			printf("NG\n");
			return 0;
		}
	}
	if (len1 > 1 && str1[0] == '0')
	{
		printf("NG\n");
		return 0;
	}
	len2 = strlen(str2);
	for (i = 0; i < len2; i++)
	{
		if (str2[i] < '0' || '9' < str2[i])
		{
			printf("NG\n");
			return 0;
		}
	}
	if (len2 > 1 && str2[0] == '0')
	{
		printf("NG\n");
		return 0;
	}
	int x = 0;
	for (i = 0; i < len1; i++)
		x = 10 * x + str1[i] - '0';
	if (x > 12345)
	{
		printf("NG\n");
		return 0;
	}
	x = 0;
	for (i = 0; i < len2; i++)
		x = 10 * x + str2[i] - '0';
	if (x > 12345)
	{
		printf("NG\n");
		return 0;
	}
	printf("OK\n");
	return 0;
}