local ffi = require 'ffi'
local C, ct = ffi.C, ffi.typeof 'uint64_t[1]'
ffi.cdef [[
int printf(const char *, ...);
int scanf(const char *, ...);
]]

C.printf("%lu\n", (function (n, k)
	C.scanf("%lu%lu",n,k)
	return (n[0]/(k[0]+1))+1
end)(ct(), ct()))