import heapq

N,M,X=map(int,input().split())
G=[{} for i in range(N)]
for j in range(M):
    u,v,c,t=map(int,input().split())
    u-=1
    v-=1
    G[u][v]=(c,t)
    G[v][u]=(c,t)

def dijkstra(s,g):
    cost=[float("inf")]*N
    prev=[None]*N
    cost[s]=0
    Q=[(0,s)]
    heapq.heapify(Q)
    while Q:
        d,v=heapq.heappop(Q)
        if d>cost[v]:
            continue
        for u in G[v]:
            c,t=G[u][v]
            #(かかる時間)=c/X+t
            money=c+X*t
            if cost[v]+money<cost[u]:
                cost[u]=cost[v]+money
                heapq.heappush(Q,(cost[u],u))
                prev[u]=v
    
    if prev[g] is None:
        return -1
    else:
        c=0
        t=0
        v=g
        u=prev[v]
        while u is not None:
            c+=G[u][v][0]
            t+=G[u][v][1]
            v=u
            u=prev[v]
        return (c+X-1)//X+t

print(dijkstra(0,N-1))