#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
const double eps = 1e-9;
const int inf = 2000000000;
const long long infLL = 90000000000000000;
inline bool checkBit(long long n, int i) { return n & (1LL << i); }
inline long long setBit(long long n, int i) {
  return n | (1LL << i);
  ;
}
inline long long resetBit(long long n, int i) { return n & (~(1LL << i)); }
int dx[] = {0, 0, +1, -1};
int dy[] = {+1, -1, 0, 0};
inline bool EQ(double a, double b) { return fabs(a - b) < 1e-9; }
inline bool isLeapYear(long long year) {
  return (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
}
inline void normal(long long &a) {
  a %= 1000000007;
  (a < 0) && (a += 1000000007);
}
inline long long modMul(long long a, long long b) {
  a %= 1000000007, b %= 1000000007;
  normal(a), normal(b);
  return (a * b) % 1000000007;
}
inline long long modAdd(long long a, long long b) {
  a %= 1000000007, b %= 1000000007;
  normal(a), normal(b);
  return (a + b) % 1000000007;
}
inline long long modSub(long long a, long long b) {
  a %= 1000000007, b %= 1000000007;
  normal(a), normal(b);
  a -= b;
  normal(a);
  return a;
}
inline long long modPow(long long b, long long p) {
  long long r = 1;
  while (p) {
    if (p & 1) r = modMul(r, b);
    b = modMul(b, b);
    p >>= 1;
  }
  return r;
}
inline long long modInverse(long long a) { return modPow(a, 1000000007 - 2); }
inline long long modDiv(long long a, long long b) {
  return modMul(a, modInverse(b));
}
const int MX = 201000;
vector<int> adjList[MX];
int bad[MX], sz[MX], k, dis[MX];
int dfs1(int u, int p) {
  sz[u] = bad[u];
  for (auto v : adjList[u])
    if (v != p) sz[u] += dfs1(v, u);
  return sz[u];
}
int dfs2(int u, int p) {
  for (auto v : adjList[u]) {
    if (v == p) continue;
    if (sz[v] > k) return dfs2(v, u);
  }
  return u;
}
void dfs3(int u, int p, int score) {
  dis[u] = score;
  for (auto v : adjList[u]) {
    if (v != p) dfs3(v, u, score + 1);
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int n;
  cin >> n >> k;
  for (int i = 0; i < 2 * k; ++i) {
    int u;
    cin >> u;
    bad[u - 1]++;
  }
  for (int i = 0; i < n - 1; ++i) {
    int u, v;
    cin >> u >> v;
    adjList[u - 1].push_back(v - 1);
    adjList[v - 1].push_back(u - 1);
  }
  dfs1(0, -1);
  int x = dfs2(0, -1);
  dfs3(x, -1, 0);
  long long ans = 0LL;
  for (int i = 0; i < n; ++i)
    if (bad[i]) ans += dis[i];
  cout << ans;
  return 0;
}
