import random
import time
import copy
import io, sys
import re

n = int(input())
res = 0
for i in range(n):
    a = input()
    l = a.split('.')

    res += int(l[0]) * int(1e10)
    if (a[0] == '-'): is_minus = True
    else: is_minus = False
    if (len(l) > 1):
        l2 = list(l[1])
        while (len(l2) < 10):
            l2.append('0')
        tmp = int(''.join(l2))
        if (is_minus): tmp *= -1
        res += tmp
s = str(res)
s2 = s[len(s) - 10 : len(s)]
print(res // int(1e10), s2, sep='.')