local ffi = require 'ffi'
local C = ffi.C

ffi.cdef [[
long atol(const char *str);
int printf(const char *fmt, ...);
]]

local n = C.atol(io.stdin:read("*l"))

local fb = n / 15
local f = n / 3 - fb
local b = n / 5 - fb

-- fiZZbuZZ: 4
-- fiZZ: 2
-- buZZ: 2

C.printf("%ld\n", fb * 4 + f * 2 + b * 2)