#include <bits/stdc++.h>
using namespace std;
const int MAX = 1000007;
vector<int> edg[MAX];
int lvl[MAX];
multiset<int>* msets[MAX];
int k;
void mergesets(int frm, int to, int height) {
  if (msets[frm]->size() > msets[to]->size()) {
    swap(msets[frm], msets[to]);
  }
  height *= 2;
  for (int x : *msets[frm]) {
    int g = *(msets[to]->begin());
    if (g + x - height > k) {
      msets[to]->insert(x);
      continue;
    }
    g = max(g, x);
    msets[to]->erase(msets[to]->begin());
    msets[to]->insert(g);
  }
  msets[frm]->clear();
}
void dfs(int u, int p = 0) {
  lvl[u] = lvl[p] + 1;
  msets[u] = new multiset<int>();
  if (edg[u].size() == 1) {
    msets[u]->insert(lvl[u]);
  }
  for (int v : edg[u]) {
    if (v == p) continue;
    dfs(v, u);
    mergesets(v, u, lvl[u]);
  }
}
int main() {
  std::ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n >> k;
  for (int i = 1; i < n; i++) {
    int u, v;
    cin >> u >> v;
    edg[u].push_back(v);
    edg[v].push_back(u);
  }
  int r = 1;
  for (int i = 2; i <= n; i++) {
    if (edg[i].size() > edg[r].size()) {
      r = i;
    }
  }
  dfs(r);
  cout << msets[r]->size() << endl;
  return 0;
}
