print((function (_, s)
	local h,r = {},0
	for e in s:gmatch("%d+") do if h[e]==nil then h[e]=0 end h[e]=h[e]+1 end
	for _,v in pairs(h) do if v==1 then r=r+1 end end
	return r
end)(io.stdin:read("*l"), io.stdin:read("*l")))