#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <queue>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint998244353;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vmi = vector<mint>;
using vvmi = vector<vmi>;
using vvvmi = vector<vvmi>;
#define all(a) (a).begin(), (a).end()
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define rep(i, n) rep2(i, 0, n)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define drep(i, n) drep2(i, n, 0)
using p = pair<int, int>;
int inf = 1e9;

int main(){
    int n, m; cin >> n >> m;
    vector<p> vp(m);
    rep(i, m){
        int u, v; cin >> u >> v;
        vp[i] = {u-1, v-1};
    }
    int k; cin >> k;
    set<int> a; rep(i, k){
        int b; cin >> b; a.insert(b-1);
    }
    vvi adj(6*n);
    rep(i, m){
        auto [u, v] = vp[i];
        if(a.count(v)){
            rep(j, 5){
                adj[u+j*n].push_back(v+j*n + n);
            }
        }else{
            rep(j, 5){
                adj[u+j*n].push_back(v);
            }
        }
        if(a.count(u)){
            rep(j, 5){
                adj[v+j*n].push_back(u+j*n + n);
            }
        }else{
             rep(j, 5){
                adj[v+j*n].push_back(u);
            }
        }
    }
    queue<int> q; q.push(0);
    vi dist(6*n, inf); dist[0] = 0;
    while(!q.empty()){
        int u = q.front(); q.pop();
        for(auto v:adj[u]){
            if(dist[v] == inf){
                dist[v] = dist[u]+1;
                q.push(v);
            }
        }
    }
    int ans = inf;
    rep(i, 5)ans = min(ans, dist[i*n-1 + n]);
    cout << (ans == inf ? -1 : ans) << endl;
    return 0;
}