static bool IsConsistent(int year, int month, int day)
{
if ( (year < 1)
|| (month < 1 || month > 12)
|| (day < 1 || day > 31)
|| (day == 31 && (month==4 || month==6 || month==9 || month==11))
|| (day > 29 && month==2)
|| (day == 29 && month==2 && !IsLeapYear(year)) )
{
return false;
}
return true;
}