require "set"

INF = 1 << 60
N, M = gets.split.map(&:to_i)
edges = Array.new(N) { [] }
M.times do |i|
  u, v = gets.split.map(&:to_i).map(&:pred)
  edges[u] << v
  edges[v] << u
end
K = gets.to_i
A = K.zero? ? [] : gets.split.map(&:to_i).map(&:pred).to_set

dists = Array.new(N) { Array.new(5, INF) }
dists[0][0] = 0

# [pos d, danger]
log = [[0, 0, 0 ]]
until log.empty?
  pos, d, danger = log.shift
  if pos == N - 1
    puts d
    exit
  end
  next if dists[pos][danger] < d
  edges[pos].each do |nxt|
    nd = A.include?(nxt) ? danger + 1 : 0
    next if nd >= 5 || dists[nxt][nd] <= d + 1
    dists[nxt][nd] = d + 1
    log << [nxt, d + 1, nd]
  end
end

puts -1