#include <bits/stdc++.h>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

template<typename T> inline istream& operator>>(istream &s, vector<T> &v) {
  for (T &t : v) s >> t;
  return s;
}

template<typename T> inline ostream& operator<<(ostream &s, const vector<T> &v) {
  for (const T &t : v) s << t << endl;
  return s;
}

template<typename T> inline T min(vector<T>& v) {return *min_element(v.begin(), v.end());}

template<typename T> inline T max(vector<T>& v) {return *max_element(v.begin(), v.end());}

template<typename T> inline void sort(vector<T>& v) {sort(v.begin(), v.end());}

template<typename T, typename Function> inline void sort(vector<T>& v, Function func) {sort(v.begin(), v.end(), func);}

template<typename T> inline void rsort(vector<T>& v) {sort(v.rbegin(), v.rend());}

template<typename T> inline void reverse(vector<T>& v) {reverse(v.begin(), v.end());}

template<typename T> inline void unique(vector<T>& v) {v.erase(unique(v.begin(), v.end()), v.end());}

template<typename T> inline void nth_element(vector<T>& v, int n) {nth_element(v.begin(), v.begin() + n, v.end());}

template<typename T> inline bool next_permutation(vector<T>& v) {return next_permutation(v.begin(), v.end());}

template<typename T> inline int find(vector<T>& v, T t) {return find(v.begin(), v.end(), t) - v.begin();}

template<typename T> inline int in(vector<T> v, T t) {return find(v, t) != (int)v.size();}

template<typename T> inline int lower_bound(vector<T>& v, T t) {return lower_bound(v.begin(), v.end(), t) - v.begin();}

template<typename T> inline int upper_bound(vector<T>& v, T t) {return upper_bound(v.begin(), v.end(), t) - v.begin();}

template<typename T> inline T accumulate(const vector<T>& v) {return accumulate(v.begin(), v.end(), T(0));}

template<typename T> inline void adjacent_difference(vector<T>& v, vector<T>& u) {adjacent_difference(v.begin(), v.end(), u.begin());}

template<typename T> inline void partial_sum(vector<T>& v, vector<T>& u) {partial_sum(v.begin(), v.end(), u.begin());}

template<typename T> inline T inner_product(vector<T>& v, vector<T>& u) {return inner_product(v.begin(), v.end(), u.begin(), T(0));}

template<typename T, typename Function> inline int count_if(vector<T> v, Function func) {return count_if(v.begin(), v.end(), func);}

template<typename T, typename Function> inline void remove_if(vector<T>& v, Function func) {v.erase(remove_if(v.begin(), v.end(), func), v.end());}

template<typename T, typename Function> inline bool any_of(vector<T> v, Function func) {return any_of(v.begin(), v.end(), func);}

int main() {
  int n, k;
  cin >> n >> k;
  vector<vector<int>> edge(n), c(n);
  for (int i = 0; i < n - 1; ++i) {
    int a, b;
    cin >> a >> b;
    --a, --b;
    edge[a].emplace_back(b);
    edge[b].emplace_back(a);
  }
  int res = n;
  if (k % 2 == 0) {
    for (int i = 0; i < n; ++i) {
      queue<int> que;
      vector<int> d(n, -1);
      que.emplace(i);
      d[i] = 0;
      int r = 0;
      while (!que.empty()) {
        int v = que.front();
        que.pop();
        ++r;
        for (int u : edge[v]) {
          if (d[u] != -1) continue;
          d[u] = d[v] + 1;
          if (d[u] > k / 2) continue;
          que.emplace(u);
        }
      }
      res = min(res, n - r);
    }
  } else {
    for (int i = 0; i < n; ++i) {
      for (int j : edge[i]) {
        queue<int> que;
        vector<int> d(n, -1);
        que.emplace(i);
        que.emplace(j);
        d[i] = 0;
        d[j] = 0;
        int r = 0;
        while (!que.empty()) {
          int v = que.front();
          que.pop();
          ++r;
          for (int u : edge[v]) {
            if (d[u] != -1) continue;
            d[u] = d[v] + 1;
            if (d[u] > k / 2) continue;
            que.emplace(u);
          }
        }
        res = min(res, n - r);
      }
    }
  }
  cout << res << endl;
}


Measured memory_bytes: 384