#include <stdio.h>
int main()
{
    int num, units, tens, hundreds, thousands;
    printf("Please enter a positive 4 digit number :");
    scanf_s("%d", &num);
    units = num % 10;
    tens = (num / 10) % 10;
    hundreds = (num / 100) % 10;
    thousands = num / 1000;
    if (num < 0)
    {
        printf("%d is a negative number. Bye bye", num);
        return 0;
    }
    if ((num >= 0 && num <= 999) || num > 9999)
    {
        printf("%d is not a 4 digit number. Bye bye", num);
        return 0;
    }
    if ((thousands - hundreds) < 0 && (hundreds - thousands) == (tens - hundreds) && (tens - hundreds) == (units - tens))
        printf("Increasing arithmetic sequence <from left to right>");
    else if ((thousands - hundreds) > 0 && (thousands - hundreds) == (hundreds - tens) && (hundreds - tens) == (tens - units))
        printf("Decreasing arithmetic sequence <from left to right>");
    else if ((hundreds == thousands) && (hundreds == tens) && (tens == units))
        printf("All 4 digits are the same");
    else if ((thousands - hundreds) <= 0 && (tens - hundreds) >= 0 && (units - tens) >= 0)
        printf("Increasing sequence <from left to right >");
    else if ((thousands - hundreds) >= 0 && (hundreds - tens) >= 0 && (tens - units) >= 0)
        printf("Decreasing sequence <from left to right>");
    else
    {
        printf("Nondecreasing and nonincreasing sequence.");
        return 0;
    }




}