#include <string>
#include <algorithm>
#include <cctype>
#include <iostream>

//...
bool isValidZipCode(const std::string& s)
{
   return s.size() == 5 && std::all_of(s.begin(), s.end(), ::isdigit);
}

using namespace std;

int main()
{
	cout << isValidZipCode("01234") << "\n";
	cout << isValidZipCode("01a34") << "\n";
	cout << isValidZipCode("9134") << "\n";
	cout << isValidZipCode("91344") << "\n";
}