Given an integer n > 0, which denotes the number of digits, the task to find total number of n-digit positive integers which are non-decreasing in nature.
A non-decreasing integer is a one in which all the digits from left to right are in non-decreasing form. ex: 1234, 1135, ..etc.
Note :Leading zeros also count in non-decreasing integers such as 0000, 0001, 0023, etc are also non-decreasing integers of 4-digits.
Examples:
Input : n = 1
Output : 10
Numbers are 0, 1, 2, ...9.
Input : n = 2
Output : 55
Input : n = 4
Output : 715
where n<10^3