In the white square $n$ times the same operation was performed: one of the smallest white squares was divided into $4$ identical squares and $2$ of them were painted black. For a given $n$ calculate how many percents of the area takes the black figure. \InputFile One integer $n~(1 \le n \le 100)$. \OutputFile Print the area of the black figure in percents, rounded to $5$ decimal digits.