代码：

#include<bits/stdc++.h>
#define int long long

using namespace std;

const int N = 4e5 + 5;

int n, m, k, maxi = 0;
bool vis[N];
int a[N];
int dis[2][N];

int tot, head[N];

struct Node{
  int to, next;
}edges[N];

void add(int u, int v){
  tot++;
  edges[tot].to = v;
  edges[tot].next = head[u];
  head[u] = tot;
}

void dijkstra(int s, int k){
  memset(vis, false, sizeof(vis));
  priority_queue<pair<int, int>> q;
	for(int i = 1; i <= n; i++) {
		dis[k][i] = 1e9;
	}
	dis[k][s] = 0;
	q.push(make_pair(dis[k][s], s));
	while(!q.empty()) {
		int x = q.top().second;
		q.pop();
		if(vis[x]) {
			continue;
		}
		vis[x] = true;
		for(int i = head[x]; i; i = edges[i].next) {
			if(1 + dis[k][x] < dis[k][edges[i].to]) {
				dis[k][edges[i].to] = 1 + dis[k][x];
				q.push(make_pair(-dis[k][edges[i].to], edges[i].to));
			}
		}
	}
}

bool cmp(int x, int y){
  return dis[1][x] < dis[1][y];
}

signed main(){
  cin >> n >> m >> k;
  for(int i = 1; i <= k; i++){
    cin >> a[i];
  }
  for(int i = 1; i <= m; i++){
    int u, v;
    cin >> u >> v;
    add(u, v);
    add(v, u);
  }
  dijkstra(1, 1);
  dijkstra(n, 2);
  sort(a + 1, a + 1 + k, cmp);
  for(int i = 1; i < k; i++){
    maxi = max(maxi, dis[1][a[i]] + dis[2][a[i + 1]] + 1);
  }
  maxi = min(maxi, dis[1][n]);
  cout << maxi;
  return 0;
}