program main
  implicit none
  integer*8::X,Y,upper,i
  integer*8,allocatable::base(:),exponents(:)
  read *,X
  upper = DINT(log(DBLE(X)))+1_8
  allocate(base(upper),exponents(upper))
  base = 0
  exponents = 0
  call factorization(X, base, exponents)

  Y = 1
  do i=1,size(base)
     if(MOD(exponents(i),2).ne.0) Y = Y * base(i)
  end do

  print '(i0)', Y
contains
  subroutine factorization(n, base, exponents)
    integer*8::n,base(:),exponents(:)
    integer*8::i,j,itr,upper
    integer*8,allocatable::furui(:)
    data itr/0/
    upper = INT(SQRT(DBLE(n)+1))
    allocate(furui(2:upper))
    furui = 0

    do i=2,upper
       if(furui(i).ne.0) cycle
       if(MOD(n, i).ne.0) cycle
       itr = itr + 1
       base(itr) = i
       do j=i+i,upper,i
          furui(j) = 1
       end do

       do j=1,upper
          n = n/i
          if(MOD(n,i).ne.0) exit
       end do
       exponents(itr) = j
       if(n.eq.1) return
    end do
    itr = itr + 1
    base(itr) = n
    exponents(itr) = 1
  end subroutine factorization
end program main