EPS = 10**10
N = int(input())
I = 0
F = 0
for _ in range(N):
    A = input()
    if '.' in A:
        C = A.find('.')
        I += int(A[:C])
        K = A[C+1:]
        while len(K) < 10:
            K += '0'
        if A[0] == '-':
            F -= int(K)
        else:
            F += int(K)
    else:
        I += int(A)
ans = str(I * EPS + F)
if len(ans) == 10:
    ans = '0' + ans
if len(ans) == 11 and ans[0] == '-':
    ans = '-0' + ans[1:]
print(f'{ans[:-10]}.{ans[-10:]}')