def parse(s)
  root = []
  stack = [root]
  s.scan(/\d+|\D/).each do |t|
    if t == '('
      stack << []
    elsif t == ')'
      st = stack.pop
      stack.last << st
    elsif t == '+'
      stack.last << '+'
    elsif t == '-'
      stack.last << '-'
    else
      stack.last << t.to_i
    end
  end
  root
end

def evaluate(ast)
  return ast if ast.instance_of?(Integer)
  ast.each_with_index.inject(0) do |s,(t,i)|
    next s if t.instance_of?(String)
    (i == 0 || ast[i - 1] == '+') ? (s + evaluate(t)) : (s - evaluate(t))
  end
end

puts evaluate(parse(gets.chomp))