#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = (1LL << 62) - (1LL << 31) - 1;

#define REP(i, init, n) for(int i = (int)(init); i < (int)(n); i++)
#define RREP(i, init, n) for(int i = (int)(init); i >= (int)(n); i--)
#define All(A) A.begin(), A.end()
#define rAll(A) A.rbegin(), A.rend()

#define vi vector<int>
#define vl vector<long>
#define vvi vector<vector<int>>
#define vvl vector<vector<long>>
#define pint pair<int, int>
#define plong pair<long, long>

int N, M, K;
vvi G;
vi A;

void solve() {
    vi dist(N * 5, 1 << 30);
    vi imap(N, 0);
    REP(i, 0, K) {
        imap[A[i]] = 1;
    }
    vvi G2(N * 5);
    REP(u, 0, N) {
        for(int v: G[u]) {
            if(imap[u] && imap[v]) {
                REP(i, 0, 4) {
                    G2[u * 5 + i].push_back(v * 5 + i + 1);
                    G2[v * 5 + i].push_back(u * 5 + i + 1);
                }
            } else {
                REP(i, 0, 4) {
                    G2[u * 5 + i].push_back(v * 5);
                    G2[v * 5 + i].push_back(u * 5);
                }
            }
        }
    }

    queue<int> que;
    que.push(0);
    dist[0] = 0;
    while(!que.empty()){
        auto cur = que.front(); que.pop();
        for(int x: G2[cur]){
            if(dist[x] > dist[cur] + 1) {
                dist[x] = dist[cur] + 1;
                que.push(x);
            }
        }
    }

    int ans = 1 << 30;
    REP(i, 0, 5) {
        ans = min(ans, dist[(N - 1) * 5 + i]);
    }
    if(ans == 1 << 30) ans = -1;
    cout << ans << endl;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    cin >> N >> M;
    G.resize(N);
    REP(i, 0, M) {
        int u, v;
        cin >> u >> v;
        u--; v--;
        G[u].push_back(v);
        G[v].push_back(u);
    }

    cin >> K;
    A.resize(K);
    REP(i, 0, K) {
        cin >> A[i];
        A[i]--;
    }
    solve();
}