from heapq import heappop, heappush
from math import inf, isinf

import sys


def printe(*args, end="\n", **kwargs):
    print(*args, end=end, file=sys.stderr, **kwargs)


def main():
    N, M, X = map(int, input().split())
    graph = [{} for _ in range(N)]
    for _ in range(M):
        u, v, C, T = map(int, input().split())
        graph[u - 1][v - 1] = (C + T * X, T)
        graph[v - 1][u - 1] = (C + T * X, T)

    distance = [(inf, inf)] * N
    distance[0] = (0, 0)
    queue = [(0, 0, 0)]
    while queue:
        c_total, c_t, c_n = heappop(queue)
        if distance[c_n][0] < c_total:
            continue
        for n_n, (n_total, n_t) in graph[c_n].items():
            if distance[n_n][0] > c_total + n_total:
                distance[n_n] = (c_total + n_total, c_t + n_t)
                heappush(queue, (c_total + n_total, c_t + n_t, n_n))
    if isinf(distance[N - 1][0]):
        print(-1)
    else:
        print(distance[N - 1][1] + (distance[N - 1]
                                    [0] - distance[N - 1][1] * X + X - 1) // X)


if __name__ == "__main__":
    main()