```    Program g01sffe
!     G01SFF Example Program Text

!     Mark 26.2 Release. NAG Copyright 2017.

!     .. Use Statements ..
Use nag_library, Only: g01sff, nag_wp
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
Integer                          :: i, ifail, la, lb, lg, lout, ltail
!     .. Local Arrays ..
Real (Kind=nag_wp), Allocatable  :: a(:), b(:), g(:), p(:)
Integer, Allocatable             :: ivalid(:)
Character (1), Allocatable       :: tail(:)
!     .. Intrinsic Procedures ..
Intrinsic                        :: max, mod, repeat
!     .. Executable Statements ..
Write (nout,*) 'G01SFF Example Program Results'
Write (nout,*)
!     Skip heading in data file

!     Read in the input vectors
Allocate (tail(ltail))

Allocate (g(lg))

Allocate (a(la))

Allocate (b(lb))

!     Allocate memory for output
lout = max(ltail,lg,la,lb)
Allocate (p(lout),ivalid(lout))

!     Calculate probability
ifail = -1
Call g01sff(ltail,tail,lg,g,la,a,lb,b,p,ivalid,ifail)

If (ifail==0 .Or. ifail==1) Then
!       Display titles
Write (nout,*)                                                         &
'  TAIL      G         A         B         P     IVALID'
Write (nout,*) repeat('-',57)

!       Display results
Do i = 1, lout
Write (nout,99999) tail(mod(i-1,ltail)+1), g(mod(i-1,lg)+1),         &
a(mod(i-1,la)+1), b(mod(i-1,lb)+1), p(i), ivalid(i)
End Do
End If

99999 Format (5X,A1,3(4X,F6.2),4X,F6.3,4X,I3)
End Program g01sffe
```