#include<stdio.h>

//sum
void CountTime(int day, int month, int year)
{
     int Dayth;
     printf("%d/%d/%d is: ", day, month, year);

     for(int i = 1; i < month;i++)
     {
         if( i == 1 || i == 3 || i == 5 || i == 7 || i ==  9 || i == 11)
         {
             if(month == 1)
             {
                Dayth = 0;
             }
             else
             {
                Dayth =  Dayth + 31;
             }

         }
         else if(i == 4 || i == 6 ||i == 8 || i == 10 || i == 12)
         {
             Dayth =  Dayth + 30;
         }
         else
         {
             Dayth =  Dayth + 28;
         }
     }

     printf("[%d]th day in year", Dayth + day);

}


void main()
{
  int day, month, year;


  //check input data
do
{
  do
  {
      printf("enter day: ");
      scanf("%d", &day);
      if(day > 31 || day <= 0)
      {
          printf(">>ERROR! day <= 30\n");
      }
  }while(day > 31 || day <= 0);

  do
  {
     printf("enter month: ");
     scanf("%d", &month);
     if(month > 12 || month < 1)
     {
         printf(">>ERROR! month >= 12\n");
     }
  }while(month > 12 || month < 1);

  if(month == 2 && day > 28 || month == 4 && day > 30 ||
       month == 6 && day > 30 || month == 8 && day > 30 ||
       month == 10 && day > 30 || month == 12 && day > 30)
  {
      printf(">>ERROR! day of month\n");
      printf("month [2] : 28 day\n");
      printf("month [4] [6] [8] [10] [12] : 30 day\n");
      printf("month [1] [3] [5] [7] [9] [11] : 31 day\n\n");
  }

}while(month == 2 && day > 28 || month == 4 && day > 30 ||
       month == 6 && day > 30 || month == 8 && day > 30 ||
       month == 10 && day > 30 || month == 12 && day > 30);

  do
  {
     printf("enter year: ");
     scanf("%d", &year);
     if(year < 2000)
     {
         printf(">>ERROR! year >= 2000");
     }
  }while(year < 2000);


  CountTime(day, month, year);
}