D = 10

wn_sum = 0
dn_sum = 0

gets
while line = gets do
  case line
  when /(-?)(\d+)\.(\d+)/ then
    sign, wn, dn = $1, $2.to_i, $3.ljust(D, "0").to_i
  when /(-?)(\d+)/
    sign, wn, dn = $1, $2.to_i, 0
  end
  if sign == "-" then
    wn_sum -= wn
    dn_sum -= dn
  else
    wn_sum += wn
    dn_sum += dn
  end
end

puts (wn_sum * 10 ** D + dn_sum).to_s.insert(-D-1, ".")