n = int(input())
a = [input() for _ in range(n)]

d = 0
for i in a:
    if "." in i:
        d = max(d, len(i.split(".")[-1]))

ans = 0
for i in a:
    sgn = 1
    if i[0] == "-":
        sgn = -1
        i = i[1:]
    if "." in i:
        x, y = i.split(".")
        x = int(x) * (10 ** d)
        y += "0" * (d - len(y))
        x += int(y)
    else:
        x = int(i) * (10 ** d)
    ans += x * sgn

ans = str(ans)
sgn = ""
if ans[0] == "-":
    sgn = "-"
    ans = ans[1:]

if d == 0:
    i = ans
    j = "0" * 10
elif d >= len(ans):
    i = "0"
    j = ans.zfill(d)
    j += "0" * max(0, 10 - len(j))
else:
    i = ans[:-d]
    j = ans[-d:]
    j += "0" * max(0, 10 - len(j))

print("{}{}.{}".format(sgn, i, j))