import random
import time
import copy
import io, sys
import re
from decimal import *

n = int(input())
res = Decimal("0.0")
for i in range(n):
    res += Decimal(input())
l = str(res).split('.')
l2 = list(l[1])
while (len(l2) < 10):
    l2.append('0')
print(l[0], ''.join(l2), sep='.')