#include <cstdio>
#include <cstring>
int main(){
    int a=0,b=0,miss=0;
    char A[6],B[6];
    scanf("%s %s",A,B);
    for(int i=0;i<strlen(A);i++){
        if('0'>A[i] || A[i]>'9' 
            || (i==0 && A[i]=='0' && strlen(A)>1)
        ){
            miss=1;break;
        }
        a=a*10+A[i]-'0';
    }
    
    for(int i=0;i<strlen(B);i++){
        if('0'>B[i] || B[i]>'9' 
            || (i==0 && B[i]=='0' && strlen(B)>1)
        ){
            miss=1;break;
        }
        b=b*10+B[i]-'0';
    }
    
    if(a>12345 || b>12345)miss=1;
    
    if(miss==0)printf("OK\n");
    else printf("NG\n");
    
    return 0;
}