N = int(input())

s0, s1 = 0, 0
for _ in range(N):
	A = input()
	
	t = A.find('.')
	if t == -1:
		s0 += int(A)
		continue
	A0 = A[:t]; A1 = A[t + 1:]
	
	A1 = A1 + '0' * (10 - len(A1))
	if A0[0] == '-':
		A1 = '-' + A1
		
	s0 += int(A0)
	s1 += int(A1)

s0 += s1 // (10 ** 10)
s1 %= 10 ** 10
	
print(str(s0) + "." + str(s1) + '0' * (10 - len(str(s1))))