A * B + C#10170

A * B + C

2 seconds

128 megabytes

Very easy

Positive integer $n$ is given. How many triplets $(A, B, C)$ (A, B, C) of positive integers satisfy $A \cdot B + C = n$ A \cdot B + C = n?

Input

One positive integer $n (2 \leq n \leq 1 0^{8})$ n~(2 \le n \le 10^8).

Print the required number of triplets.

Example 1

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Example 2

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For $n = 3$ n = 3 there are exactly three triplets:

(A, B, C)

A \cdot B + C = n

n (2 \leq n \leq 1 0^{8})

n = 3

(1, 1, 2)

1 \cdot 1 + 2 = 3

(1, 2, 1)

1 \cdot 2 + 1 = 3

(2, 1, 1)

2 \cdot 1 + 1 = 3