from heapq import heappop, heappush

n, m, x = map(int, input().split())
edges = [[] for _ in range(n)]
for _ in range(m):
    u, v, c, t = map(int, input().split())
    c += t * x
    u -= 1
    v -= 1
    edges[u].append((v, c))
    edges[v].append((u, c))

dist = [1 << 60] * n
dist[0] = 0
hq = [0]
while hq:
    tmp = heappop(hq)
    d = tmp // n
    pos = tmp - d * n
    if dist[pos] < d:
        continue
    for to, cost in edges[pos]:
        if dist[to] > d + cost:
            dist[to] = d + cost
            heappush(hq, to + n * dist[to])

ans = (dist[-1] + x - 1) // x if dist[-1] != 1 << 60 else -1
print(ans)