/**
 *    author:  tourist
 *    created: 04.05.2019 16:36:43       
**/
#include <bits/stdc++.h>

using namespace std;

string to_string(string s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

const int N = 2010;

template <typename T>
class graph {
 public:
  struct edge {
    int from;
    int to;
    T cost;
  };

  vector<edge> edges;
  vector<vector<int>> g;
  int n;

  graph(int _n) : n(_n) {
    g.resize(n);
  }

  virtual int add(int from, int to, T cost) = 0;
};

template <typename T>
class forest : public graph<T> {
 public:
  using graph<T>::edges;
  using graph<T>::g;
  using graph<T>::n;

  forest(int _n) : graph<T>(_n) {
  }

  int add(int from, int to, T cost = 1) {
    assert(0 <= from && from < n && 0 <= to && to < n);
    int id = (int) edges.size();
    assert(id < n - 1);
    g[from].push_back(id);
    g[to].push_back(id);
    edges.push_back({from, to, cost});
    return id;
  }
};

template <typename T>
class dfs_forest : public forest<T> {
 public:
  using forest<T>::edges;
  using forest<T>::g;
  using forest<T>::n;

  vector<int> pv;
  vector<int> pe;
  vector<int> order;
  vector<int> pos;
  vector<int> end;
  vector<int> sz;
  vector<int> root;
  vector<int> depth;
  vector<T> dist;

  dfs_forest(int _n) : forest<T>(_n) {
  }

  void init() {
    pv = vector<int>(n, -1);
    pe = vector<int>(n, -1);
    order.clear();
    pos = vector<int>(n, -1);
    end = vector<int>(n, -1);
    sz = vector<int>(n, 0);
    root = vector<int>(n, -1);
    depth = vector<int>(n, -1);
    dist = vector<T>(n);
  }

  void clear() {
    pv.clear();
    pe.clear();
    order.clear();
    pos.clear();
    end.clear();
    sz.clear();
    root.clear();
    depth.clear();
    dist.clear();
  }

 private:
  void do_dfs(int v) {
    pos[v] = (int) order.size();
    order.push_back(v);
    sz[v] = 1;
    for (int id : g[v]) {
      if (id == pe[v]) {
        continue;
      }
      auto &e = edges[id];
      int to = e.from ^ e.to ^ v;
      depth[to] = depth[v] + 1;
      dist[to] = dist[v] + e.cost;
      pv[to] = v;
      pe[to] = id;
      root[to] = (root[v] != -1 ? root[v] : to);
      do_dfs(to);
      sz[v] += sz[to];
    }
    end[v] = (int) order.size() - 1;
  }

  void do_dfs_from(int v) {
    depth[v] = 0;
    dist[v] = T{};
    root[v] = v;
    pv[v] = pe[v] = -1;
    do_dfs(v);
  }

 public:
  void dfs(int v, bool clear_order = true) {
    if (pv.empty()) {
      init();
    } else {
      if (clear_order) {
        order.clear();
      }
    }
    do_dfs_from(v);
  }

  void dfs_all() {
    init();
    for (int v = 0; v < n; v++) {
      if (depth[v] == -1) {
        do_dfs_from(v);
      }
    }
    assert((int) order.size() == n);
  }
};

template <typename T>
class lca_forest : public dfs_forest<T> {
 public:
  using dfs_forest<T>::edges;
  using dfs_forest<T>::g;
  using dfs_forest<T>::n;
  using dfs_forest<T>::pv;
  using dfs_forest<T>::pos;
  using dfs_forest<T>::end;
  using dfs_forest<T>::depth;

  int h;
  vector<vector<int>> pr;

  lca_forest(int _n) : dfs_forest<T>(_n) {
  }

  inline void build_lca() {
    assert(!pv.empty());
    int max_depth = 0;
    for (int i = 0; i < n; i++) {
      max_depth = max(max_depth, depth[i]);
    }
    h = 1;
    while ((1 << h) <= max_depth) {
      h++;
    }
    pr.resize(n);
    for (int i = 0; i < n; i++) {
      pr[i].resize(h);
      pr[i][0] = pv[i];
    }
    for (int j = 1; j < h; j++) {
      for (int i = 0; i < n; i++) {
        pr[i][j] = (pr[i][j - 1] == -1 ? -1 : pr[pr[i][j - 1]][j - 1]);
      }
    }
  }

  inline bool anc(int x, int y) {
    return (pos[x] <= pos[y] && end[y] <= end[x]);
  }

  inline int go_up(int x, int up) {
    assert(!pr.empty());
    up = min(up, (1 << h) - 1);
    for (int j = h - 1; j >= 0; j--) {
      if (up & (1 << j)) {
        x = pr[x][j];
        if (x == -1) {
          break;
        }
      }
    }
    return x;
  }

  inline int lca(int x, int y) {
    assert(!pr.empty());
    if (anc(x, y)) {
      return x;
    }
    if (anc(y, x)) {
      return y;
    }
    for (int j = h - 1; j >= 0; j--) {
      if (pr[x][j] != -1 && !anc(pr[x][j], y)) {
        x = pr[x][j];
      }
    }
    return pr[x][0];
  }
};

int lca[N][N];
pair<int, int> que[N * N];
bitset<N> nei[N];
bitset<N> subtree[N];
bitset<N> to_root[N];

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  lca_forest<int> g(n);
  for (int i = 0; i < n - 1; i++) {
    int x, y;
    cin >> x >> y;
    x--; y--;
    g.add(x, y);
  }
  g.dfs(0);
  g.build_lca();
  for (int i = 0; i < n; i++) {
    for (int j = i; j < n; j++) {
      lca[i][j] = lca[j][i] = g.lca(i, j);
    }
  }
  for (int i = 0; i < n; i++) {
    nei[i].set(i);
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (lca[i][j] == i) {
        subtree[i].set(j);
        to_root[j].set(i);
      }
    }
  }
  for (int i = 0; i < m; i++) {
    cin >> que[i].first >> que[i].second;
    que[i].first--;
    que[i].second--;
    nei[que[i].first].set(que[i].second);
    nei[que[i].second].set(que[i].first);
  }
  bitset<N> full;
  for (int i = 0; i < n; i++) {
    full.set(i);
  }
  for (int b = 0; b < m; b++) {
    int x = que[b].first;
    int y = que[b].second;
    bitset<N> valid;
    int z = lca[x][y];
    if (z == y) {
      swap(x, y);
    }
    if (z == x) {
      int u = g.go_up(y, g.depth[y] - g.depth[x] - 1);
      valid = full ^ subtree[u] ^ subtree[y] ^ to_root[x] ^ to_root[y];
    } else {
      valid = subtree[x] ^ subtree[y] ^ to_root[x] ^ to_root[y];
      valid.flip(z);
    }
    bitset<N> news = (nei[x] ^ nei[y]) & valid;
    for (int i = (int) news._Find_first(); i != N; i = (int) news._Find_next(i)) {
      int j = (nei[x][i] ? y : x);
      debug(x, y, i, j);
      que[m++] = make_pair(i, j);
      nei[i].set(j);
      nei[j].set(i);
    }
  }
  cout << m << '\n';
  return 0;
}


Measured memory_bytes: 35200