N, M, K = gets.split.map &:to_i
edges = []
M.times.map{
  a, b, c = gets.split.map &:to_i
  edges << [a, b, c] << [b, a, c]
}
tollages = gets.split.map &:to_i
starts = []
edges.each{|a,b,c|
  starts << a if c == tollages[0]
}
starts.uniq!
checked = [false] * -~N

dfs = ->pos, i{
  if i == K
    checked[pos] = true
    return
  end
  edges.each{|a,b,c|
    next if c != tollages[i]
    next if a != pos
    dfs[b, i+1]
  }
}
starts.each{|start|
  dfs[start, 1]
}
p checked.count(true)
puts (1..N).select{|i|checked[i]}*" "