def main():
    N = int(input())
    sum_ = 0
    for _ in range(N):
        num_str = input()
        if "." not in num_str:
            sum_ += int(num_str + "0"*10)
            continue
        integer, fractional = num_str.split(".")
        sum_ += int(integer + fractional + "0"*(10-len(fractional)))

    if sum_ < 0:
        print("-", end="")

    sum_ = abs(sum_)
    if sum_ == 0:
        print(0.0000000000)
        return

    if sum_ < 10000000000:
        print("0." + "0"*(10-len(str(sum_))) + str(sum_))
    else:
        print(str(sum_)[:-10] + "." + str(sum_)[-10:])


if __name__ == "__main__":
    main()