from decimal import Decimal
N=int(input())
ans=Decimal(0)
for _ in range(N):
    x=Decimal(input())
    ans+=x
ans=str(ans)
if "." in ans:
    p=ans.index(".")
    ans+="0"*(10-(len(ans)-p-1))
else:
    ans+="."+"0"*10
print(ans)