print((function (s, f)
	local x,op,y = s:match("([+-]?%d+)([+-]+)(%d+)")
    return (op=="--" and f(x)+f("-"..y)) or ((op=="+" or op=="++") and f(x)-f(y)) or f(x)+f(y)
end)(io.stdin:read("*l"), tonumber))