n = int(input())
ans = 0
for _ in range(n):
    a = input()
    if '.' in a:
        ai, af = a.split('.')
        p = 10 - len(af)
        ans += int(ai + af + '0' * p)
    else:
        ans += int(a) * 10**10
minus = ans < 0
i, f = divmod(abs(ans), 10**10)
i, f = str(i), str(f)
if len(f) < 10:
    f = '0' * (10 - len(f)) + f
if minus:
    i = '-' + i
print(i + '.' + f)