PPM P3 is bitmap image file format, the specification is as following.

The header consist of characters P3, width and height of the image, and 
maximum value of color component (we use 255)
after that follows the pixel as three integer R G B

Example:

P3
3 1
255
0 0 255 255 0 0 0 255 0

Above is image with three column and one row, with pixels (0, 0, 255), (255, 0, 0) (0, 255, 0)

You are given some PPM P3 image via stdin, you have to change all the yellow pixel (FFFF00)
to black pixel (000000) and output it as PPM P3 image via stdout