pages = open("links.txt").readlines()[1:]

page_map = {}
for page in pages:
	p = page.strip().split(', ')
	src = p[1]
	dst = p[2]
	rank = int(p[0])
	if src not in page_map.keys():
		page_map[src] = []
	page_map[src].append({
		"dst": dst,
		"rank": rank
		})


def traverse(src, current_percentage):
	total_rank = sum([info["rank"] for info in page_map[src]]) * 1.0
	min_rank = min([info["rank"] for info in page_map[src]])
	total_sum = 0.0
	for dst_info in page_map[src]:
		dst = dst_info["dst"]
		if (dst == "finish.html"):
			return current_percentage
		new_current = dst_info["rank"] / total_rank * current_percentage
		if (dst_info["rank"] != min_rank):
			total_sum += traverse(dst, new_current)
	return total_sum



current = "start.html"

current_percentage = 100.0

print 16200000 * traverse(current, current_percentage)