program n1271
    implicit none
    integer k,i
    real(8)::ans=0
    read*,k
    if(k==0)then
        ans=1.644934066848226436472
    else
        do i=1,k
            ans=ans+1/real(i)
        end do
        ans=ans/real(k)
    end if
    print'(f0.10)',ans
end program n1271