For a provided integer $k$, find the maximum value of $m+n$, where $1 \leqslant m,n \leqslant k$ and $(n^2 - nm - m^2)^{2} = 1$.

Note: The answer can exceed the range of a 32-bit integer.

Input format

The only line of the input contains one integer $k$.

Output format

Print the maximum value of $m+n$, where $1 \leqslant m,n \leqslant k$ and $(n^2 - nm - m^2)^{2} = 1$.

Constraints

$1 \leqslant k \leqslant 10^{18}$