```    Program g01sdfe
!     G01SDF Example Program Text

!     Mark 26.1 Release. NAG Copyright 2017.

!     .. Use Statements ..
Use nag_library, Only: g01sdf, nag_wp
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
Integer                          :: i, ifail, ldf1, ldf2, lf, lout,      &
ltail
!     .. Local Arrays ..
Real (Kind=nag_wp), Allocatable  :: df1(:), df2(:), f(:), p(:)
Integer, Allocatable             :: ivalid(:)
Character (1), Allocatable       :: tail(:)
!     .. Intrinsic Procedures ..
Intrinsic                        :: max, mod, repeat
!     .. Executable Statements ..
Write (nout,*) 'G01SDF Example Program Results'
Write (nout,*)

!     Skip heading in data file

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

Allocate (f(lf))

Allocate (df1(ldf1))

Allocate (df2(ldf2))

!     Allocate memory for output
lout = max(lf,ldf1,ldf2,ltail)
Allocate (p(lout),ivalid(lout))

!     Calculate probability
ifail = -1
Call g01sdf(ltail,tail,lf,f,ldf1,df1,ldf2,df2,p,ivalid,ifail)

If (ifail==0 .Or. ifail==1) Then
!       Display titles
Write (nout,*)                                                         &
'   TAIL      F        DF1       DF2       P      IVALID'
Write (nout,*) repeat('-',56)

!       Display results
Do i = 1, lout
Write (nout,99999) tail(mod(i-1,ltail)+1), f(mod(i-1,lf)+1),         &
df1(mod(i-1,ldf1)+1), df2(mod(i-1,ldf2)+1), p(i), ivalid(i)
End Do
End If

99999 Format (5X,A1,3(4X,F6.2),4X,F6.3,4X,I3)
End Program g01sdfe
```