local bit = require 'bit'

function add(a, b)
	while b ~= 0 do
		local c = bit.lshift(bit.band(a, b), 1)
		a = bit.bxor(a, b)
		b = c
	end
	return a
end

local a, b = io.stdin:read("*n"), io.stdin:read("*n")
print(add(a, b))