import heapq
n, m, x = list(map(int, input().split()))
g = [[] for _ in range(n)]
for i in range(m):
	a, b, c, t = list(map(int, input().split()))
	a -= 1
	b -= 1
	g[a].append((b, t*x + c))
	g[b].append((a, t*x + c))

INF = 10**18
pq = [(0, 0)]
dist = [INF] * n
while pq:
	d, v = heapq.heappop(pq)
	if dist[v]!=INF:
		continue
	dist[v] = d
	for u, c in g[v]:
		if dist[u]==INF:
			heapq.heappush(pq, (d+c, u))

if dist[n-1]==INF:
	print(-1)
else:
	print((dist[n-1]+x-1)//x)