import sys
import heapq
input = sys.stdin.readline
INF = 10**18
def dijkstra(start, adj, n):
dist = [INF] * (n + 1)
dist[start] = 0
pq = [(0, start)] # (distance, node)
while pq:
d, u = heapq.heappop(pq)
if d > dist[u]:
continue
for v, w in adj[u]:
if dist[v] > d + w:
dist[v] = d + w
heapq.heappush(pq, (dist[v], v))
return dist
# Input
n, m = map(int, input().split())
adj = [[] for _ in range(n + 1)]
for _ in range(m):
a, b, c = map(int, input().split())
adj[a].append((b, c))
adj[b].append((a, c))
S, T, U, V = map(int, input().split())
# Step 1: distances from S and T
dS = dijkstra(S, adj, n)
dT = dijkstra(T, adj, n)
D = dS[T]
# Step 2: build modified graph
adj2 = [[] for _ in range(n + 1)]
for u in range(1, n + 1):
for v, w in adj[u]:
cost = w
if dS[u] + w + dT[v] == D or dS[v] + w + dT[u] == D:
cost = 0
adj2[u].append((v, cost))
# Step 3: shortest path from U to V
dist = [INF] * (n + 1)
dist[U] = 0
pq = [(0, U)]
while pq:
d, u = heapq.heappop(pq)
if d > dist[u]:
continue
for v, w in adj2[u]:
if dist[v] > d + w:
dist[v] = d + w
heapq.heappush(pq, (dist[v], v))
print(dist[V])
