A mixed fraction is defined recursively as follows:
One can draw a view of a mixed fraction using ASCII characters as described below:
We want you to write a program to calculate the value of a mixed fraction from its figure.
Some 90 degree clockwise rotated figures of a number of mixed fractions are given in the input file. In the first line of each rotated mixed fraction n < 300 and m < 15000 , the length and the width of the figure, are written. In the next m lines the figure i s described ('-' is replaced with '|'). Note that each line will consists of exactly n characters so any number of spaces may be used in the shape, but anyway, the shape of the figure satisfies description explained above.
The input ends with a line containing two zeroes.
For each test case write its value in a separate line. Your answer must be rounded to two digits after decimal point and the output must contain exactly two digits after the decimal point.