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:
                i -= 1
                f += max_f
        else:
            f += af * pow(10, p)
            if f >= max_f:
                i += 1
                f -= max_f
    else:
        i += int(a)
i, f = str(i), str(f)
if len(f) < 10:
    f = f + '0' * (10 - len(f))
print(i + '.' + f)