from heapq import *

def dijkstra():
    D[0] = (0, 0)
    q = [((0, 0), 0)]
    while q:
        dm, u = heappop(q)
        d, m = dm
        if dm > D[u]: continue
        for v, c, t in E[u]:
            a = 0
            if -m < c:
                a = -((-m - c) // X)
                t += a
            c -= X * a
            if D[v] > (d + t, c + m):
                D[v] = (d + t, c + m)
                heappush(q, (D[v], v))
    return

N, M, X = map(int, input().split())
UV = [list(map(int, input().split())) for _ in range(M)]
INF = 10 ** 12
D = [(INF, 0)] * N
E = [[] for _ in range(N)]
for u, v, c, t in UV:
    u -= 1;
    v -= 1
    E[u].append((v, c, t))
    E[v].append((u, c, t))
dijkstra()
ans = D[N - 1][0]
if ans == INF:
    print(-1)
else:
    print(ans)