int keitai()
{
	int numar, c;

	cin >> numar;

	c = (numar/1000000) % 10;

	if(c == 2 || c == 3 || c == 4 || c == 5 || c == 6 || c == 7 || c == 8)
		cout << 77;
	else
		cout << 7;

	return 0;
}

int main()
{
	keitai();

	return 0;
}