N = int(input())
ans = 0
for i in range(N):
    n = input()
    pm = 1
    if n[0] == "-":
        n = n[1:]
        pm = -1
    if "." in n:
        X, Y = n.split(".")
        ans += int(X) * (10 ** 10) * pm
        ans += int(Y + "0" * (10 - len(Y))) * pm
    else:
        ans += int(n) * (10 ** 10) * pm
flag = 0
if ans < 0:
    flag = 1
ans = abs(ans)
X = ans // (10 ** 10)
Y = str(ans % (10 ** 10))
Y = "0" * (10 - len(Y)) + Y
S = str(X) + "." + str(Y)
if flag:
    S = "-" + S
print(S)