// 2022 IUSB Programming Competition
// Round 1 Problem 2
// Credit Card Number
// Solution by Liguo Yu

#include <iostream>
#include <string>
using namespace std;

int main()
{
	char c1[17];
	cin.getline(c1, 17);

	int total = 0;

	string s = c1;

	for (int i = 0; i < 16; i++)
	{
		char c = s.at(i);
		char * s = new char[2];
		s[0] = c;
		total = total + atoi(s);
	}

	if (total % 29 == 5) cout << "valid";
	else  cout << "not valid";

  return 1;
}