n, m = gets.split.map(&:to_i)
g = Array.new(n) { Array.new() }
m.times do
    u, v = gets.split.map(&:to_i)
    u -= 1
    v -= 1
    g[u] << v
    g[v] << u
end
k = gets.to_i
a = []
if k > 0 then
    a = gets.split.map(&:to_i)
end
exist = Array.new(n, false)
a.each do |i|
    exist[i - 1] = true
end

$MX = 1_000_000_000
dist = Array.new(n) { Array.new(5, $MX) }
q = []
dist[0][0] = 0
q << [0, 0]
while q.size > 0
    v, x = q.shift
    g[v].each do |nv|
        nx = x
        if exist[nv] then
            nx += 1
        else
            nx = 0
        end
        if nx < 5 && dist[nv][nx] == $MX then
            dist[nv][nx] = dist[v][x] + 1
            q << [nv, nx]
        end
    end
end

ans = $MX
(0..4).each do |j|
    if ans > dist[n - 1][j] then
        ans = dist[n - 1][j]
    end
end
if ans == $MX then
    ans = -1
end

puts ans