program name
    use,intrinsic :: iso_fortran_env
    implicit none
    integer(int64):: x,mx,ans

    read*, x
    mx = mod(x,11_8)
    ans = 2_8*(x/11_8)

    if (mx > 0) then
        ans=ans+1
        if (mx/7 > 0) ans=ans+1
    end if 
    print'(i0)', ans
end program name