import heapq
N,M,X = map(int,input().split())
G = {i:[] for i in range(1,N+1)}
for _ in range(M):
    u,v,c,t = map(int,input().split())
    if u==v:continue
    G[u].append((v,t*X+c))
    G[v].append((u,t*X+c))
INFTY = 10**16
dist = [INFTY for _ in range(N+1)]
dist[1] = 0
visited = [0]*(N+1)
heap=[(0,1)]
while heap:
    d,u = heapq.heappop(heap)
    if d>dist[u]:continue
    visited[u] = 1
    for v,c in G[u]:
        if visited[v]==0 and d+c<dist[v]:
            dist[v] = d+c
            heapq.heappush(heap,(d+c,v))
if dist[N]>=INFTY:
    print(-1)
else:
    print((dist[N]+X-1)//X)