#include <stdio.h>

const char *wd(int year, int month, int day) {
  static const char *weekdayname[] = {"Monday", "Tuesday",
        "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
  size_t JND =                                                     \
          day                                                      \
        + ((153 * (month + 12 * ((14 - month) / 12) - 3) + 2) / 5) \
        + (365 * (year + 4800 - ((14 - month) / 12)))              \
        + ((year + 4800 - ((14 - month) / 12)) / 4)                \
        - ((year + 4800 - ((14 - month) / 12)) / 100)              \
        + ((year + 4800 - ((14 - month) / 12)) / 400)              \
        - 32045;
  return weekdayname[JND % 7];
}