inputCount = int(input())

mul = pow(10, 10)

list = []
for i in range(inputCount):
    seisu = input().rstrip()
    syousu = ""
    if("." in seisu):
        (seisu,syousu) = seisu.split(".")
    while len(syousu) < 10:
        syousu += "0"

    if seisu[0:1] == "-":
        syousu = "-" + syousu

    list.append(int(seisu) * mul + int(syousu))


ans = str(sum(list))

ans = ans[0:len(ans) - 10] + "." + ans[len(ans) - 10:]
print(ans)