N = int(input())
cum = 0
for n in range(N):
    a = input()
    if '.' in a:
        a_1, a_2 = a.split('.')
        a1 = int(a_1) * 10**10
        a2 = int(a_2) * 10 ** (10 - len(a_2))
        if a_1.startswith('-'):
            a = a1 - a2
        else:
            a = a1 + a2
    else:
        a = int(a) * 10 ** 10
    cum += a
if abs(cum) < 10**10:
    if cum > 0:
        str_cum = '0' * (11 - len(str(cum))) + str(cum)
    elif cum < 0:
        str_cum = '-' + '0' * (11 - len(str(abs(cum)))) + str(abs(cum))
    else:
        str_cum = '0' * 11
else:
    str_cum = str(cum)
print(str_cum[:-10] + '.' + str_cum[-10:])