program Sort_N_data 
         implicit none
         integer :: N , a , I , J
         real , allocatable , dimension (:) :: di_date(:)
         real*8  :: data1 , temp
         character(50) :: filename
         write(*,*) " OPEN File Name =? EX.(date.dat, ... etc) "
         read(*,*) filename
         open (unit=20 ,file=filename,status='OLD')
         open (unit=30 ,file='date3.dat',status='REPLACE')
         read(20,*) N
         write(30,*)N
         write(*,*)N
         allocate(di_date(N)) 
         a=1 
         do a = 1 , N
           read(20,*) data1
           di_date(a)=data1
         end do

         do I=N-1 , 1 , -1
            do J= 1, I
                if (di_date(J) < di_date(J+1)) then
                   temp=di_date(J)
                   di_date(J)=di_date(J+1)
                   di_date(J+1)=temp
                 end if
             end do
          end do
          
         I=1
         do I =1, N
         write(*,*) di_date(I)
         write(30,*) di_date(I)
         end do
         deallocate (di_date) 
         close(20)
         close(30)
         write(*,*)"SAVE in 'date3,dat' " 
         stop 
         end program Sort_N_data