from heapq import heapify, heappop, heappush
N, M, X = map(int, input().split())
G = [[] for _ in range(N)]
for _ in range(M):
    u, v, C, T = map(int, input().split())
    u -= 1; v -= 1
    G[u].append((v, C + T * X))
    G[v].append((u, C + T * X))
H = [(0, 0)]
heapify(H)
dist = [10 ** 18] * N
dist[0] = 0
while len(H) > 0:
    d, u = heappop(H)
    if d > dist[u]: continue    
    for v, w in G[u]:
        if dist[v] > dist[u] + w:
            dist[v] = dist[u] + w
            heappush(H, (dist[v], v))
if dist[N - 1] == 10 ** 18:
    print(-1)
else:
    print((dist[N - 1] + X - 1) // X)