#include <bits/stdc++.h>
using namespace std;
int k;
vector<int> v[((int)(1e6 + 5))];
pair<int, int> dfs(int n, int par, int dis) {
  pair<int, int> ans, tmp;
  ans.second = ((int)(1e7));
  ans.first = 0;
  for (int i = 0; i < v[n].size(); i++) {
    if (v[n][i] != par) {
      tmp = dfs(v[n][i], n, dis + 1);
      ans.first += tmp.first;
      if (ans.second + tmp.second - 2 * dis <= k) {
        ans.first--;
        ans.second = max(ans.second, tmp.second);
      } else
        ans.second = min(ans.second, tmp.second);
    }
  }
  if (ans.first == 0) {
    ans.second = dis;
    ans.first = 1;
  }
  return ans;
}
int main() {
  int n, i, a, b;
  scanf("%d %d", &n, &k);
  for (i = 1; i < n; i++) {
    scanf("%d %d", &a, &b);
    v[b].push_back(a);
    v[a].push_back(b);
  }
  for (i = 1; i <= n; i++) {
    if (v[i].size() > 1) {
      printf("%d\n", dfs(i, 0, 0).first);
      return 0;
    }
  }
}
