/p{( )dup 0 4 3 roll put print}def/f(%stdin)(r)file def f{9 string readline
pop(e)gt{{f read pop p f read not{{p}loop}if}loop}{{f read not{{count -1 roll p
p}loop}if}loop}ifelse}stopped
Note that non-ascii characters in the above source code will be escaped (such as \x9f).