Program Main
   Implicit None
   Integer :: limit

   Do 
     Print *, "FactorialÀ»  ±¸ÇÏ°íÀÚ ÇÏ´Â ¼ö n À» ³Ö¾î¶ó"
     Read *, limit
     If (limit < 0) Then
        Print *, ' Your number is negative, Bye!! ' ; Exit
     EndIf
     Print *, 'The Factorial of ',limit,' is ',factorial(limit)
   EndDo
Contains

  Recursive Integer Function Factorial(n) Result(fac)
    Integer :: n
    If (n==0) Then ; fac =1 
    Else ; fac = n*Factorial(n-1) ; Endif
  End Function Factorial

End Program