import sys
input=lambda:sys.stdin.readline().rstrip()
N=int(input())
ans=0
#L=list(map(int,input().split()))
for i in range(N):
	S=input()
	if not '.' in S:
		down=0
	else:
		down=S[::-1].index('.')
	S=S.replace('.','')
	ans+=int(S)*pow(10,10-down)
minus=(ans<0)
ans=str(abs(ans))
ans='0'*max(0,11-len(ans))+ans
print('-'*minus+ans[:-10]+'.'+ans[-10:])