n = int(input())

ret = 0
for _ in range(n):
  a = input()
  p = a.find('.')
  if p == -1:
    a += "0000000000"
  else:
    m = 10 - len(a) + p + 1
    a = a[:p] + a[p+1:]
    a += "".join('0' for _ in range(m))
  ret += int(a)


sign = "" if ret >= 0 else "-"
d = abs(ret) // 10000000000
f = abs(ret) % 10000000000

print("{}{}.{:010}".format(sign, d, f))