abc131_a_security.cpp

// Security | https://atcoder.jp/contests/abc131/tasks/abc131_a
// Time: O(1); extra space: O(1).
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>

void solve() {
    std::string s;
    std::cin>>s;
    bool good=true;
    for(int i=1;i<4;++i)good=good&&s[i]!=s[i-1];
    std::cout<<(good?"Good":"Bad")<<'\n';
}
int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    solve();
}