#include <stdio.h>
#include <stdlib.h>

int main(void) {
  int day, month, days;
  printf("What day are you interested in?");
  scanf("%d", &day);
  printf("Of which month?");
  scanf("%d", &month);
  if ((day <0) || (day > 31) || (month<0) || (month>12))
    printf("Erroneous input.\n");
  else {
    days = day-1;
    /* A shorter approach than done in 'whatday.c'.  Here I
     * start off by pretending that all months are length 31, 
     * and add 31*(month -1) to the count of days.  After that
     * I adjust the total depending on the irregular months gone
     * past.  A shorter, but less clear, approach.  */
    days = 31*(month-1) +days;
    if ((month >=3) && (month <5))
      days = days -2;
    else if ((month >=5) && (month < 7)) 
      days = days -3;
    else if ((month >=7) && (month < 10))
      days = days -4;
    else if ((month >= 10) && (month <12))
      days = days -5;
    else if (month == 12)
      days = days -6;
    days = days % 7;
    if (days == 0)
      printf("It was a Sunday\n");
    else if (days == 1)
      printf("It was a Monday\n");
    else if (days == 2)
      printf("It was a Tuesday\n");
    else if (days == 3)
      printf("It was a Wednesday\n");
    else if (days == 4)
      printf("It was a Thursday\n");
    else if (days == 5)
      printf("It was a Friday\n");
    else 
      printf("It was a Saturday\n");
  }
  return EXIT_SUCCESS;
}