n = int(input())
m = int(input())
root = int(input()) - 1
edges = []
tree = []
max_weight = 0
union = [i for i in range(n)]
for i in range(m):
tmp = list( map(int, input().split()) )
tmp[0] = tmp[0] - 1
tmp[1] = tmp[1] - 1
edges.append( tmp )
edges.sort(key = lambda x:(x[2]) )
def findRoot(x):
if union[x] == x:
return x
else:
return findRoot(union[x])
for i in range(m):
edge = edges[i]
u = edge[0]
v = edge[1]
u_root = findRoot(u)
v_root = findRoot(v)
if u_root != v_root:
#连接
uv_max = max(u_root,v_root)
uv_min = min(u_root,v_root)
union[uv_min] = uv_max
tree.append(edge)
max_weight = max(max_weight, edge[2])
else:
continue
if len(tree) == n-1:
break
print(max_weight)
#print(tree)
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