Problem:
Score : 300 points

Problem Statement

Given is a positive integer N.
How many tuples (A,B,C) of positive integers satisfy A \times B + C = N?

Constraints

2 \leq N \leq 10^6

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer.

Sample Input 1

3

Sample Output 1

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).

Sample Input 2

100

Sample Output 2

473

Sample Input 3

1000000

Sample Output 3

13969985

Solution in Python (3.8.2) (judge verdict: Runtime Error)


n=int(input())
#d = [list(map(int,input().split())) for _ in range(s)]

def p(val):
    print(val)

count = 0

#cは1以上で、問題文からN-1 a*b <=N-1のものをもとめる
#aを1からふやしてく、cはaとbが決まれば自動歴に決まるので、
for i in range(1,n):
    

    

        
p(count)