#include<iostream>
#include<cmath>
#include<vector>
using namespace std;

int main(){
    string A,B;
    cin>>A>>B;
    bool ng=(A.length()<=5)&&(B.length()<=5)&&!(A.length()>1&&A[0]=='0')&&!(B.length()>1&&B[0]=='0');
    double inta=0,intb=0;
    vector<int> aa,ba;
    for(int i=0; i<A.length(); i++){
        if(A[i]<'0'||A[i]>'9')ng=false;
        aa.push_back(A[i]-'0');
    }
    for(int i=0; i<B.length(); i++){
        if(B[i]<'0'||B[i]>'9')ng=false;
        ba.push_back(B[i]-'0');
    }
    for(int i=aa.size()-1; i>=0; i--){
        inta+=aa[i]*pow(10.0,fabs(i-(int)aa.size()+1));
    }
    for(int i=ba.size()-1; i>=0; i--){
        intb+=ba[i]*pow(10.0,fabs(i-(int)ba.size()+1));
    }
    cout<<((ng&&inta<=12345&&intb<=12345)?("OK"):("NG"))<<endl;
    return 0;
}