import sys
input = sys.stdin.readline

from heapq import heappush, heappop
inf = float('inf')
def dijkstra(s, g, G):
    # ゴールがない場合はg=-1とする。

    N = len(G)

    def cost(v, m):
        return v * N + m

    dist = [inf] * N
    mindist = [inf] * N
    seen = [False] * N
    Q = [cost(0, s)]
    while Q:
        c, m = divmod(heappop(Q), N)
        if seen[m]:
            continue
        seen[m] = True
        dist[m] = c
        if m == g:
            return dist

        #------heapをアップデートする。--------
        for u, C in G[m]:
            if seen[u]:
                continue
            newdist = dist[m] + C

            #------------------------------------
            if newdist >= mindist[u]:
                continue
            mindist[u] = newdist
            heappush(Q, cost(newdist, u))
    return dist


N, M, X = map(int, input().split())
G = [[] for i in range(N)]
for i in range(M):
    u, v, c, t = map(int, input().split())
    u, v = u - 1, v - 1
    G[u].append((v, t * X + c))
    G[v].append((u, t * X + c))
    
D = dijkstra(0, N - 1, G)
print((D[-1]+X-1)//X) if D[-1] != inf else print("-1")