from heapq import heappush, heappop

N, M, X = map(int, input().split())
G = [[] for _ in range(N)]
for _ in range(M):
    u, v, C, T = map(int, input().split())
    G[u-1].append((v-1, C+T*X))
    G[v-1].append((u-1, C+T*X))

INF = 10**18
def dijkstra(start):
    dist = [INF]*N
    dist[start] = 0
    visited = [False]*N
    que = [(0, start)]
    while que:
        d, now = heappop(que)
        if visited[now]:
            continue
        visited[now] = True
        for next, weight in G[now]:
            if dist[now]+weight < dist[next]:
                dist[next] = dist[now]+weight
                heappush(que, (dist[next], next))
    return dist

dist = dijkstra(0)
if dist[-1] == INF:
    print(-1)
else:
    print((dist[-1]+X-1)//X)