import heapq

def min_time_to_reach(N, M, X, roads):
    graph = [[] for _ in range(N + 1)]
    for u, v, C, T in roads:
        work_time = C // X + (1 if C % X != 0 else 0)  
        graph[u].append((v, work_time + T))
        graph[v].append((u, work_time + T))  
    distances = [float('inf')] * (N + 1)
    distances[1] = 0  
    queue = [(0, 1)]  

    while queue:
        total_time, u = heapq.heappop(queue)
        if total_time > distances[u]:
            continue
        for v, time in graph[u]:
            if distances[u] + time < distances[v]:
                distances[v] = distances[u] + time
                heapq.heappush(queue, (distances[v], v))
    return distances[N] if distances[N] != float('inf') else -1
N, M, X = map(int, input().split())
roads = [tuple(map(int, input().split())) for _ in range(M)]

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