      PROGRAM encloseAll
      IMPLICIT NONE
      integer(16) :: n
      integer(16),allocatable :: x(:),y(:)
      integer(16) :: i,l,r,k
      real(16) :: cx,cy,rad,len,eps=0.0000001,ans=100000
      
      
      read*,n
      allocate(x(n),y(n))
      do i = 1,n
        read*,x(i),y(i)
      end do
      
      out:do l = 1,n-1
        in:do r = l+1,n
          cx = real(x(l)+x(r))/2.
          cy = real(y(l)+y(r))/2.
          rad = sqrt( real(x(l)-x(r))**2.+real(y(l)-y(r))**2. )/2.
          
          do k = 1,n
            len = sqrt( (real(x(k)-cx))**2.+(real(y(k)-cy))**2. )
            if( len>rad )then
              cycle in
            end if
          end do
          if( ans >= rad )then
            ans = rad
          end if
        end do in
      end do out
      
      print*,ans
      
      END PROGRAM