program y888
    implicit none
    integer(8)::N,N_sqrt,i
    integer(8)::result=0

    read(5,*)N
    N_sqrt=int(sqrt(real(N)))

    do i=1,N_sqrt
        if(mod(N,i)==0)then
            result=result+i
            if(i/=N/i)then
                result=result+N/i
            end if
        end if
    end do

    print'(i0)',result
    
end program y888