#include <iostream>
using namespace std;
int main (){
    string str;
    while(getline(cin, str)){
        if(str.size() <= 8)
            {cout << "NG" << endl; continue;}
        int num = 0, other = 0, lower = 0, upper = 0;
        bool flag = false;
        for(int i = 0; i < str.size(); ++i){
            if(isdigit(str[i]))    num = 1; 
            else if(islower(str[i]))    lower = 1; 
            else if(isupper(str[i]))    upper = 1; 
            else    other = 1;
            if((num + lower + upper + other) >= 3)
                {flag = true; break;}
        }
        if(!flag)
            {cout << "NG" << endl; continue;}
        for(int i = 0; i < str.size()-3; ++i){
            string ss = str.substr(0,i) + str.substr(i+3);
            if(ss.find(str.substr(i, 3)) != string::npos)
                {flag = false; break;}
        }
        if(flag)
            cout << "OK" << endl;
        else    
            cout << "NG" << endl;
    }
}