Score : 300 points
Given is a positive integer N. How many tuples (A,B,C) of positive integers satisfy A \times B + C = N?
Input is given from Standard Input in the following format:
N
Print the answer.
3
3
There are 3 tuples of integers that satisfy A \times B + C = 3: (A, B, C) = (1, 1, 2), (1, 2, 1), (2, 1, 1).
100
473
1000000
13969985