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

    sa = sb = 0
    for i in range(N):
        s = input()
        sign = True
        if s[0] == '-':
            s = s[1:]
            sign = False

        a, b = (s + '.').split('.', maxsplit=2)[:2]
        if sign:
            sa += int(a)
            sb += int((b + '000000000000')[:10])
        else:
            sa -= int(a)
            sb -= int((b + '000000000000')[:10])

    sa += sb // 10000000000
    sb %= 10000000000
    print(sa, '.', sb, sep='')

if __name__ == '__main__':
    solve()