def digitSum(x):
	total = 0
	while x>0:
		total+=x%10
		x=x//10
	return total
		

def solve(A):
	max_num = {}
	ans = -1
	
	for x in A:
		s = digitSum(x)
		
		if s in max_num:
			ans = max(ans, max_num[s] + x)
			
		max_num[s] = max(max_num.get(s,0), x)
	return ans

def main():
	n = int(input())
	A = list(map(int, input().split()))
	
	print(solve(A))
	
if __name__=="__main__":
	main()