# https://yukicoder.me/problems/no/2739

import heapq

MAX_INT = 10 ** 18

def main():
    N, M, X = map(int, input().split())
    next_nodes = [[] for _ in range(N)]
    for _ in range(M):
        u, v, C, T = map(int, input().split())
        next_nodes[u - 1].append((v - 1, X * T + C))
        next_nodes[v - 1].append((u - 1, X * T + C))
    
    fix = [MAX_INT ] * N
    seen = [MAX_INT] * N
    seen[0] = 0
    queue = []
    heapq.heappush(queue, (0, 0))
    while len(queue) > 0:
        cost, v = heapq.heappop(queue)
        if fix[v] < MAX_INT:
            continue

        fix[v] = cost
        for w, c in next_nodes[v]:
            if fix[w] < MAX_INT:
                continue

            new_cost = c + cost
            if seen[w] > new_cost:
                seen[w] = new_cost
                heapq.heappush(queue, (new_cost, w))
    
    if fix[N - 1] == MAX_INT:
        print(-1)
    else:
        x = fix[N - 1]
        answer = x // X + (1 if x % X > 0 else 0)
        print(answer)




if __name__ == "__main__":
    main()