program sette

 implicit none

 integer  :: i,j,n
 real*8, allocatable :: a(:,:)
 real*8   :: sum1,sum2,sum3,sum4,tmp

 !1)
 open(10,file='input')
 read(10,*) n
 allocate(a(n,n))
 do i=1,n
    do j=1,n
       read(10,*) a(i,j)
    enddo   
 enddo   

 do i=1,n
    write(*,*) (a(i,j),j=1,n)
 enddo

 !2) 
 sum1=0.d0
 sum2=0.d0
 do i=1,n-1
    sum1=sum1+a(i,i+1)
 enddo   
 do i=1,n-1
    sum2=sum2+a(i+1,i)
 enddo   
 write(*,*) 'Upper sum',sum1
 write(*,*) 'Lower sum',sum2

 sum3=0.d0
 do i=n,1,-1
    sum3=sum3+a(i,n+1-i)
 enddo
 write(*,*) 'Antidiagonal sum', sum3 

 !3)
 call make_op(a,n,sum4) 
 write(*,*) 'Sum4',sum4

 !4)
 tmp=sum1-sum2-sum3+sum4

 open(11,file='output')
 if (tmp.gt.1.d0) then
    write(*,*) 'Upper elements printed'
    do i=1,n-1
       write(11,100) a(i,i+1)
    enddo   
 else   
    write(*,*) 'Lower elements printed'
    do i=1,n-1
       write(11,100) a(i+1,i)
    enddo   
 endif   

 close(10)
 close(11)

 deallocate(a)

100 format(F12.4)

 stop

end program  

subroutine make_op(a,n,res)

 implicit none

 integer, intent(in) :: n
 real*8, intent(in) :: a(n,n)
 real*8, intent(out) :: res

 integer  :: i,j,itmp

 res=1.d0

 do i=1,n
    do j=1,n
       itmp=i+j
       if (mod(itmp,2).ne.0) then 
           res=res*a(i,j)
       endif     
    enddo   
 enddo   
 
 return

end subroutine make_op