:m m="mc"
  : =""5:
  : ="b"2:
  f:bc + b = :u-f c="$ + $b"f:bc
  f:bc - b = :u-f c="$ - $b"f:bc
  f:bc * b = :u-f c="$ * $b"f:bc
  f:bc  b = :u-f c="u($  $b)"f:bc
  f:bc  b = :u-f c="$  $b"f:bc
 :