require 'bigdecimal'

n = gets.to_i
a = []
n.times do
  s = gets.chomp
  unless /^([-]?)(\d+)(?:[.](\d+))?$/o =~ s
    warn 'must not happen'
    exit 1
  end
  sign = $1
  i, d = "#{sign}#{$2}", "#{sign}0.#{$3 || 0}"
  a << [BigDecimal(i), BigDecimal(d)]
end

int = a.map{|i, d| i }.inject(:+)
decimal = a.map{|i, d| d }.inject(:+)
d_int = decimal.to_i
int += d_int
decimal -= d_int

printf "%d.%010d\n", int, (decimal.abs * (10 ** 10))