from collections import deque,defaultdict
N,M,X=map(int,input().split())
G=[[] for _ in range(N)]
C=defaultdict(int)
T=defaultdict(int)
for _ in range(M):
    u,v,c,t=map(int,input().split())
    u-=1;v-=1
    G[u].append(v)
    G[v].append(u)
    C[(u,v)]=c
    C[(v,u)]=c
    T[(u,v)]=t
    T[(v,u)]=t
vis=[(-1,-1,-1) for _ in range(N)]
attr=defaultdict(tuple)
Q=deque()
attr[0]=(0,0,0)
Q.append(0)
while Q:
    now=Q.popleft()
    m,c,t=attr[now]
    del attr[now]
    vis[now]=(m,c,t)
    for nxt in G[now]:
        if c+C[(now,nxt)]>m:
            work=(m-c+C[(now,nxt)]+X-1)//X
        else:
            work=0
        if vis[nxt]==(-1,-1,-1) or t+T[(now,nxt)]+work<vis[nxt][2]:
            if nxt in attr.keys():
                mm,cc,tt=attr[nxt]
                if t+T[(now,nxt)]+work<tt:
                    attr[nxt]=(m+X*work,c+C[(now,nxt)],t+T[(now,nxt)]+work)
            else:
                attr[nxt]=(m+X*work,c+C[(now,nxt)],t+T[(now,nxt)]+work)
                Q.append(nxt)
print(vis[N-1][2])