import heapq

def aa(m):
    global n
    hq=[];heapq.heappush(hq,(0,m))
    res=[1<<60]*n;res[m]=0
    while hq:
        q,w=heapq.heappop(hq)
        if res[w]<q:
            continue
        for i,j in v[w]:
            if res[i]>q+j:
                res[i]=q+j
                heapq.heappush(hq,(res[i],i))
    return res

n,m,p,q,t=map(int,input().split());q-=1;p-=1
v=[[] for i in range(n)]
for i in range(m):
    a,b,c=map(int,input().split());a-=1;b-=1
    v[a].append((b,c));v[b].append((a,c))
x,y,z=aa(0),aa(p),aa(q)
if max(x[q]*2,x[p]*2)>t:
    print(-1);exit()
if x[q]+x[p]+y[q]<=t:
    print(t);exit()
ans=0
for i in range(n):
    for j in range(n):
        if max(y[i]+y[j],z[i]+z[j])+x[i]+x[j]<=t:
            ans=max(ans,t-max(y[i]+y[j],z[i]+z[j]))
print(ans)