Problem Statement

Penguinman likes multiples of $3$. Having nothing to do, Penguinman defined something called a more perfect multiple of $3$ and decided to count how many there are.

According to Penguinman's definition, an integer $X$ is a "perfect multiple of $3$" if it satisfies all of the following $3$ conditions.

• $X$ is positive.
• $X$ is a multiple of $3$ with at least $2$ digits in base $10$ notation.
• Let $D$ be the number of digits of $X$ in base $10$ notation. For any $i,j (0≤i<j < D)$, the sum of the digit in the $10^i$ place and the digit in the $10^j$ place is a multiple of $3$.

Since there are infinitely many such integers, Penguinman decided to count the perfect multiples of $3$ that are at most $N$, but is in despair at how many there are.

It can't be helped, so please count them on Penguinman's behalf.

Input

$N$

• $10≤N≤10^9$
• $N$ is an integer

Output

Print the number of perfect multiples of $3$ that are at most $N$ on $1$ line.

Sample

15

2

300

31

100000

1038