#include <bits/stdc++.h>
using namespace std;

using ll = int64_t;

constexpr ll INF = (1LL << 60) - 1;

ll N, M;
vector<ll> U, V;
vector<vector<ll>> G;
ll K;
vector<bool> A;

void input() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> N >> M;
    U.resize(M), V.resize(M);
    for (ll i=0; i<M; ++i) {
        cin >> U[i] >> V[i];
        --U[i], --V[i];
    }
    cin >> K;
    A.resize(N, false);
    for (ll i=0; i<K; ++i) {
        ll a;
        cin >> a;
        A[a-1] = true;
    }
}

vector<bool> VISITED;

vector<ll> C;

void bfs(ll start) {
    C.assign(N*5, INF);
    C[start] = 0;
    deque<ll> que;
    que.emplace_back(start);
    while (!que.empty()) {
        ll v = que.front();
        que.pop_front();
        for (const auto& e : G[v]) {
            if (C[e] != INF) continue;
            C[e] = C[v] + 1;
            que.emplace_back(e);
        }
    }
}

void solve() {
    G.resize(N*5);
    for (ll i=0; i<M; ++i) {
        if (A[V[i]]) {
            for (ll j=0; j<4; ++j) {
                G[U[i]+N*j].emplace_back(V[i]+N*(j+1));
            }
        } else {
            for (ll j=0; j<=4; ++j) {
                G[U[i]+N*j].emplace_back(V[i]);
            }
        }
        if (A[U[i]]) {
            for (ll j=0; j<4; ++j) {
                G[V[i]+N*j].emplace_back(U[i]+N*(j+1));
            }
        } else {
            for (ll j=0; j<=4; ++j) {
                G[V[i]+N*j].emplace_back(U[i]);
            }
        }
    }
    bfs(0);
    if (C[N-1] == INF) cout << -1 << "\n";
    else cout << C[N-1] << "\n";
}

int main() {
    input();
    solve();
    return 0;
}

/* 考察

*/