from decimal import *
N=int(input())
s = 0
for i in range(N):
    A = input()
    d = Decimal(A)*10**10
    s += int(d)
if s==0:
    print(0.0000000000)
else:
    s = str(s)
    ans = s[:-10] + '.' + s[-10:]
    print(ans)