program ciao

nr1 = 12
nr2 = 12
nr3 = 12

  do i = 1, nr1
   do j = 1, nr2
    do k = 1, nr3
      ir = i + (j-1) * nr1 + (k-1) * nr1 * nr2
      kk = (ir-1)/nr1/nr2+1
      jj = 1+(ir-(kk-1)*nr1*nr2-1)/nr1
      ii = ir - ( (jj-1) * nr1 + (kk-1) * nr1 * nr2  )
      write (6,*) i,j,k, ii-i,jj-j,kk-k
    enddo
   end do
  end do

end