integer::N,M,i,pos
  integer,allocatable::PQ(:,:)
  read *, N, M
  allocate(PQ(2,M))
  read *, PQ

  pos = n
  do i=1, M
     if (pos.eq.PQ(1,i)) then
        pos = PQ(2,i)
     else if(pos.eq.PQ(2,i)) then
        pos = PQ(1,i)
     end if
  end do
  print '(i0)',pos
end program