Problem2146--ABC conjecture(AtCoder 227_c)

2146: ABC conjecture(AtCoder 227_c)

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Time Limit : 1.000 sec  Memory Limit : 128 MB

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Description

Problem Statement

You are given a positive integer N.

Find the number of triples of positive integers (A,B,C)such that A<=B<=C and ABC<=N.

The Constraints guarantee that the answer is less than 2**63.



Constraints

  • 1<=N<=10**11
  •  N is an integer


Input

N

Output

Print the answer.

Sample Input Copy 

4

Sample Output Copy 

5

HINT

There are five such triples: (1,1,1),(1,1,2),(1,1,3),(1,1,4),(1,2,2).

Source/Category

 
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