#include <iostream>
#include <cstdint>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
using namespace std;

struct Func_print
{
    void is_true(bool yes) {
        cout << (yes ? "Yes" : "No") << '\n';
    };
    void print_v_str(vector<string> v) {
        for (auto s : v) {
            for (auto c : s) {
                cout << c << ' ';
            }
            cout << '\n';
        }
    }

    void print_vv(vector<vector<int>> vv) {
        for (auto v : vv) {
            for (auto d : v) {
                cout << d << ' ';
            }
            cout << '\n';
        }
    }
};
Func_print Out;//出力用

#define REP(i, n) for (int i = 0; i < (n); i++)
#define VEC(type, name, n) vector<type> name(n); REP(i, n) cin >> name.at(i)
#define VV(type, name, h, w) vector<vector<type>> name(h, vector<type>(w)); REP(i, h) REP(j, w) cin >> name.at(i).at(j)
#define ALL(iterable) begin(iterable), end(iterable)



int main() {
///////////////////////////////
//お約束
    ios::sync_with_stdio(false);//printfとcoutを混在しないように注意
    //doubleの桁数指定は以下を使用する
    //cout << fixed << setprecision() << y << endl; 
    cin.tie(nullptr);
////////////////////////////////

    int N, M; cin >> N >> M;
    vector<vector<int>> edges(N+1, vector<int>());
    REP(i, M) {
        int u, v; cin >> u >> v;
        edges[u].push_back(v);
        edges[v].push_back(u);
    }

    vector<bool> is_yiwiy9(N+1, false);//右寄りしか勝たん！！
    int K; cin >> K;
    REP(i, K) {
        int a; cin >> a;
        is_yiwiy9[a] = true;
    }

    const int IS_NOT_PATH = 10;
    vector<int> min_cnt_yiwiy9(N+1, IS_NOT_PATH);
    bool success = false;

    vector<int> path;
    const int64_t INF = INT64_MAX;
    int64_t ans = INF;
    auto dfs = [&](auto self, int v) {
        if (success) return;
        if (v == N) {
            ans = min(ans, (int64_t)path.size() - 1);
            return;
        }

        int cnt_now = min_cnt_yiwiy9[v];
        for (auto nv : edges[v]) {
            int cnt_next = cnt_now;
            if (is_yiwiy9[nv]) cnt_next ++;
            else cnt_next = 0;
            
            if (min_cnt_yiwiy9[nv] <= cnt_next) continue;
            if (cnt_next >= 5) continue;
            min_cnt_yiwiy9[nv] = cnt_next;

            path.push_back(nv);
            self(self, nv);
            path.pop_back();

        }
    };

    min_cnt_yiwiy9[1] = 0; 
    path.push_back(1);
    dfs(dfs, 1);

    if (ans == INF) ans = -1;
    cout << ans << endl;
}