from heapq import heappop, heappush
from collections import defaultdict

n, m, x = map(int, input().split())
G = defaultdict(list)
for _ in range(m):
    u, v, c, t = map(int, input().split())
    u -= 1
    v -= 1
    G[u].append((v, c + t * x))
    G[v].append((u, c + t * x))
INF = 10**18
DP = [INF for _ in range(n)]
DP[0] = 0
H = [(0, 0)]
while H:
    cc, cp = heappop(H)
    if cc > DP[cp]:
        continue
    for np, dc in G[cp]:
        nc = cc + dc
        if nc >= DP[np]:
            continue
        DP[np] = nc
        heappush(H, (nc, np))
ans = DP[n - 1]
if ans == INF:
    ans = -1
else:
    ans = (ans + x - 1) // x
print(ans)