: fac ( num -- out )  
  dup 1 > if dup 1- recurse * then ;

: 0bye ( num -- ) 
  0= if bye then ;

: xdrop ( count -- )
  0 do drop loop ;

: >single ( c-addr u1 -- u2 )
  0 0 2swap >number 3 xdrop ;

30 chars buffer: buf

." Number: " 
buf 30 accept dup 0bye
buf swap >single

." Factorial of " dup . ." is "

fac . cr