n = int(input())
i, f = 0, 0
max_f = 10**10
for _ in range(n):
    a = input()
    if '.' in a:
        ai, af = a.split('.')
        ai = int(ai)
        i += ai
        p = 10 - len(af)
        af = int(af)
        if a[0] == '-':
            f -= af * pow(10, p)
            # if f < 0:
            #     if i == 0 and not minus:
            #         minus = True
            #     else:
            #         i -= 1
            #         f += max_f
        else:
            f += af * pow(10, p)
            # if f >= max_f:
            #     if i == 0 and minus:
            #         minus = False
            #     else:
            #         i += 1
            #         f -= max_f
    else:
        i += int(a)
i, f = str(i), str(f)
if i == '0' and f[0] == '-':
    i = '-' + i
    f = f[1:]
elif len(f) > 10 or f[0] == '-':
    q, f = divmod(int(f), max_f)
    i = str(int(i) + q)
    f = str(f)
if len(f) < 10:
    f = '0' * (10 - len(f)) + f
print(i + '.' + f)