require 'bigdecimal'


n = BigDecimal.new(gets)

ans = BigDecimal.new("0")
i = 0
while i<n do
	x = BigDecimal.new(gets)
	ans += x
	i += 1
end

if ans < 0 then
	ans = BigDecimal(ans).ceil(10)
else
	ans = BigDecimal(ans).floor(10)
end

s = ans.to_s("F")

arr = s.split(".")

print arr[0]
print "."
arr[1] += "0000000000"
print arr[1][0..9]
print "\n"