subroutine mother(i,mi)
      include ?
      implicit none

      integer i,mi,j
      integer jda,jbv,jd0,jd2,jdprev

      jdprev = 0
      mi = 0

      do j=1,ngenpart

        jda = idagenpart(j)
        jbv = jda/20000000
        jd0 = jda - jbv*20000000
        jd2 = jd0/4000

        if(jd2.gt.0.and.jd2.ne.jdprev) then

          if(jdprev.lt.i.and.jd2.ge.i) then
            mi = j
            goto 999
          endif

          jdprev = jd2

        endif

      enddo

999   continue

      end