n = int(input())
ans = 0
for i in range(n):
    s = input()
    if "." in s:
        l, r = s.split(".")
    else:
        l = s
        r = "0"
    a = 1
    if l[0] == "-":
        a = -1
        l = l[1:]
    rdigit = ["0" for i in range(10)]
    for i, v in enumerate(r):
        rdigit[i] = v
    l = int(l) * 10000000000
    r = int("".join(rdigit))
    d = a * (l + r)
    ans += d
    
b = ""
if ans < 0:
    b = "-"
ans = str(abs(ans))
l = len(ans)
if l < 10:
    for i in range(10 - l):
        ans = '0' + ans

ans = ans[:-10] + "." + ans[-10:]
if ans[0] == ".":
    ans = "0" + ans
ans = b + ans

print(ans)