// O(N^2) naiivne algoritm

#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define llong long long
#define cin fin

using namespace::std;

int main()
{
    ifstream fin("transsis.txt");
    ofstream fout("transval.txt");

    int N, K;
    cin >> N >> K;

    vector<vector<int> > adj(N, vector<int>(0));
    vector<bool> participants(N, 0);

    for (int i = 0; i < N - 1; i++) {
        int u, v;
        cin >> u >> v;
        u--;
        v--;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i = 0; i < K; i++) {
        int u;
        cin >> u;
        u--;
        participants[u] = 1;
    }
    fin.close();

    llong answ = 2e18;
    for (int i = 0; i < N; i++) { // leiame iga tipu jaoks O(N) ajas transpordikulud, vastus on miinimum üle leitud väärtuste
        llong sum = 0;
        vector<int> visited(N, 0);
        queue<pair<int, int> > Q;
        Q.push({i, 0});
        while(!Q.empty()) {
            auto cur = Q.front();
            Q.pop();
            int pos = cur.first, dist = cur.second;

            visited[pos] = 1;
            if (participants[pos]) {
                sum += (llong)dist * dist;
            }

            for (auto j : adj[pos]) {
                if (!visited[j]) {
                    Q.push({j, dist + 1});
                }
            }
        }
        answ = min(answ, sum);
    }
    fout << answ;
    return 0;
}