First Occurrence in Pascal's Triangle Sequence

The famous Pascal's Triangle is arranged as follows:

If we list all the numbers of the triangle in order from top to bottom and from left to right, we obtain the sequence:

$1,1,1,1,2,1,1,3,3,1,1,4,6,4,1,\ldots$

Given a positive integer $N$, find the 1-indexed position where $N$ appears for the first time in this sequence.

inputFormat

The input consists of a single line containing a positive integer $N$.

outputFormat

Output a single integer, which is the 1-indexed position of the first occurrence of $N$ in the sequence formed by reading the Pascal's Triangle row by row from left to right.

sample

1

1