import heapq
import math  

def dijkstra(graph, start, end, X):
    pq = [(0, start)]
    visited = set()
    while pq:
        time, node = heapq.heappop(pq)
        if node in visited:
            continue
        visited.add(node)
        if node == end:
            return math.ceil(time)  
        for neighbor, cost, travel_time in graph[node]:
            if neighbor not in visited:
                total_time = travel_time + math.ceil(cost / X)
                heapq.heappush(pq, (time + total_time, neighbor))
    return -1

def solve(N, M, X, roads):
    graph = {i: [] for i in range(1, N+1)}
    for u, v, C, T in roads:
        graph[u].append((v, C, T))
        graph[v].append((u, C, T))  
    min_time = dijkstra(graph, 1, N, X)
    return min_time

N, M, X = map(int, input().split())
roads = [tuple(map(int, input().split())) for _ in range(M)]

min_time = solve(N, M, X, roads)
print(min_time - 1 if min_time != -1 else -1)