def solve():
    N = int(input())

    a = 0
    for i in range(N):
        s = input()

        p = s.find('.')
        if p == -1:
            s += '0000000000'
        else:
            n = 10 - (len(s) - p - 1)
            s = s[:p] + s[p + 1:]
            if n > 0:
                 s += '0' * n
        a += int(s)

    s = str(a)
    print(s[:-10], '.', s[-10:], sep='')


if __name__ == '__main__':
    solve()