Competitions
Math problems 6-8 grade
A * B + C
Positive integer n is given. How many tuples (A, B, C) of positive integers satisfy A * B + C = n?
Input data
One positive integer n (2 ≤ n ≤ 10^8).
Output data
Print the required number of tuples.
Examples
Input example #1
3
Output example #1
3
Input example #2
11
Output example #2
27