1      subroutine parenthese_ps(ch,n)
2      CHARACTER*1024 CH,chch
3      j = 1
4      do i=1,n
5        if (ch(i:i).eq.'(') then
6c
7c char(92) = \
8c
9          chch(j:j+1) = char(92)//'('
10          j = j+2
11        elseif (ch(i:i).eq.')') then
12          chch(j:j+1) = char(92)//')'
13          j = j+2
14        else
15          chch(j:j) = ch(i:i)
16          j = j+1
17        endif
18      enddo
19      if (j-1.ne.n) then
20        n = j-1
21        ch(1:n) = chch(1:n)
22        ch(n+1:n+1) = char(0)
23      endif
24      end
25