#line 2 "library/template.hpp"
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.hpp>
#else
template <class T>
concept Streamable = requires(ostream os, T &x) { os << x; };
template <class mint>
concept is_modint = requires(mint &x) {
    { x.val() } -> std::convertible_to<int>;
};
#define debug(...)
#endif
template <Streamable T> void print_one(const T &value) { cout << value; }
template <is_modint T> void print_one(const T &value) { cout << value.val(); }
void print() { cout << '\n'; }
template <class T, class... Ts> void print(const T &a, const Ts &...b) {
    print_one(a);
    ((cout << ' ', print_one(b)), ...);
    cout << '\n';
}
template <ranges::range Iterable>
    requires(!Streamable<Iterable>)
void print(const Iterable &v) {
    for(auto it = v.begin(); it != v.end(); ++it) {
        if(it != v.begin())
            cout << " ";
        print_one(*it);
    }
    cout << '\n';
}
using vi = vector<int>;
using vii = vector<vector<int>>;
using pii = pair<int, int>;
using ll = long long;
using vl = vector<ll>;
using vll = vector<vl>;
using pll = pair<ll, ll>;
#define all(v) begin(v), end(v)
template <class T> void UNIQUE(T &v) {
    ranges::sort(v);
    v.erase(unique(all(v)), end(v));
}
template <typename T> inline bool chmax(T &a, T b) {
    return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
    return ((a > b) ? (a = b, true) : (false));
}
// https://trap.jp/post/1224/
template <class... T> constexpr auto min(T... a) {
    return min(initializer_list<common_type_t<T...>>{a...});
}
template <class... T> constexpr auto max(T... a) {
    return max(initializer_list<common_type_t<T...>>{a...});
}
template <class... T> void input(T &...a) { (cin >> ... >> a); }
template <class T> void input(vector<T> &a) {
    for(T &x : a)
        cin >> x;
}
#define INT(...)                                                               \
    int __VA_ARGS__;                                                           \
    input(__VA_ARGS__)
#define LL(...)                                                                \
    long long __VA_ARGS__;                                                     \
    input(__VA_ARGS__)
#define STR(...)                                                               \
    string __VA_ARGS__;                                                        \
    input(__VA_ARGS__)
#define REP1_0(n, c) REP1_1(n, c)
#define REP1_1(n, c)                                                           \
    for(ll REP_COUNTER_##c = 0; REP_COUNTER_##c < (ll)(n); REP_COUNTER_##c++)
#define REP1(n) REP1_0(n, __COUNTER__)
#define REP2(i, a) for(ll i = 0; i < (ll)(a); i++)
#define REP3(i, a, b) for(ll i = (ll)(a); i < (ll)(b); i++)
#define REP4(i, a, b, c) for(ll i = (ll)(a); i < (ll)(b); i += (ll)(c))
#define overload4(a, b, c, d, e, ...) e
#define rep(...) overload4(__VA_ARGS__, REP4, REP3, REP2, REP1)(__VA_ARGS__)
ll inf = 3e18;
vl dx = {1, -1, 0, 0};
vl dy = {0, 0, 1, -1};
template <class T> constexpr T floor(T x, T y) noexcept {
    return x / y - ((x ^ y) < 0 and x % y);
}
template <class T> constexpr T ceil(T x, T y) noexcept {
    return x / y + ((x ^ y) >= 0 and x % y);
}
// yの符号に関わらず非負で定義 \bmod:texコマンド
template <class T> constexpr T bmod(T x, T y) noexcept {
    T m = x % y;
    return (m < 0) ? m + (y > 0 ? y : -y) : m;
}
template <std::signed_integral T> constexpr int bit_width(T x) noexcept {
    return std::bit_width((uint64_t)x);
}
template <std::signed_integral T> constexpr int popcount(T x) noexcept {
    return std::popcount((uint64_t)x);
}
constexpr bool kth_bit(auto n, auto k) { return (n >> k) & 1; }
#line 3 "library/graph/graph-template.hpp"
/**
 * @brief Graph Template(グラフテンプレート)
 * @see https://ei1333.github.io/library/graph/graph-template.hpp
 */
template <class T = ll> struct Edge {
    int from, to;
    T cost;
    int idx;
    Edge() = default;
    Edge(int from, int to, T cost = 1, int idx = -1)
        : from(from), to(to), cost(cost), idx(idx) {}
    Edge &operator=(const int &x) {
        to = x;
        return *this;
    }
    operator int() const { return to; }
};
template <class T = ll> struct Graph {
    using cost_type = T;
    vector<vector<Edge<T>>> g;
    int es; // edge_size
    Graph() = default;
    explicit Graph(int n) : g(n), es(0) {};
    int size() const { return ssize(g); }
    void add_directed_edge(int from, int to, T cost = 1) {
        g[from].emplace_back(from, to, cost, es++);
    }
    void add_edge(int from, int to, T cost = 1) {
        g[from].emplace_back(from, to, cost, es);
        g[to].emplace_back(to, from, cost, es++);
    }
    vector<Edge<T>> &operator[](const int &k) { return g[k]; }
    const vector<Edge<T>> &operator[](const int &k) const { return g[k]; }
    void read(int m, int padding = -1, bool weighted = false,
              bool directed = false) {
        for(int i = 0; i < m; ++i) {
            int a, b;
            T c(1);
            cin >> a >> b;
            a += padding;
            b += padding;
            if(weighted)
                cin >> c;
            if(directed)
                add_directed_edge(a, b, c);
            else
                add_edge(a, b, c);
        }
    }
};
#line 3 "test.cpp"
int main() {
    INT(n, m);
    Graph<bool> g(n);
    g.read(m);
    INT(k);
    vector<bool> a(n, false);
    rep(k) {
        INT(ai);
        a[--ai] = true;
    }
    vector d(n, vi(5, -1));
    queue<pii> q;
    q.push({0, 0});
    d[0][0] = 0;
    while(q.size()) {
        auto [i, num] = q.front();
        q.pop();
        for(auto to : g[i]) {
            int nex = a[to] ? num + 1 : 0;
            if(nex == 5 or d[to][nex] != -1)
                continue;
            d[to][nex] = d[i][num] + 1;
            q.push({to, nex});
        }
    }
    int ans = -1;
    rep(i, 5) {
        if(ans == -1)
            ans = d[n - 1][i];
        else if(d[n - 1][i] != -1) {
            chmin(ans, d[n - 1][i]);
        }
    }
    debug(d);
    print(ans);
}