#include<iostream>
#include<string>
#include<unordered_set>
using namespace std;
int main () {
string s;
while (getline(cin, s)) {
// 要求1
int len = s.size();
if (len <= 8) {
cout << "NG" << endl;
continue;
}
// 要求2
unordered_set<int> set;
for (int i = 0; i < len; ++i) {
if (s[i] >= 'A' && s[i] <= 'Z')
set.insert(1);
else if (s[i] >= 'a' && s[i] <= 'z')
set.insert(2);
else if (s[i] >= '0' && s[i] <= '9')
set.insert(3);
else
set.insert(4);
}
if (set.size() < 3) {
cout << "NG" << endl;
continue;
}
// 要求3
int flag = 0;
for (int i = 0; i < len - 3; ++i) {
for (int j = i + 1; j < len - 2; ++j) {
if (s.substr(i, 3) == s.substr(j, 3)) {
flag = 1;
break;
}
}
if (flag == 1)
break;
}
if (flag == 1) {
cout << "NG" << endl;
continue;
}
cout << "OK" << endl;
}
return 0;
}