#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
inline void smin(T &a, const U &b) {
  if (a > b) a = b;
}
template <typename T, typename U>
inline void smax(T &a, const U &b) {
  if (a < b) a = b;
}
template <class T>
inline void gn(T &first) {
  char c, sg = 0;
  while (c = getchar(), (c > '9' || c < '0') && c != '-')
    ;
  for ((c == '-' ? sg = 1, c = getchar() : 0), first = 0; c >= '0' && c <= '9';
       c = getchar())
    first = (first << 1) + (first << 3) + c - '0';
  if (sg) first = -first;
}
template <class T1, class T2>
inline void gn(T1 &x1, T2 &x2) {
  gn(x1), gn(x2);
}
template <class T1, class T2, class T3>
inline void gn(T1 &x1, T2 &x2, T3 &x3) {
  gn(x1, x2), gn(x3);
}
template <class T1, class T2, class T3, class T4>
inline void gn(T1 &x1, T2 &x2, T3 &x3, T4 &x4) {
  gn(x1, x2), gn(x3, x4);
}
template <class T>
inline void print(T first) {
  if (first < 0) {
    putchar('-');
    return print(-first);
  }
  if (first < 10) {
    putchar('0' + first);
    return;
  }
  print(first / 10);
  putchar(first % 10 + '0');
}
template <class T>
inline void println(T first) {
  print(first);
  putchar('\n');
}
template <class T>
inline void printsp(T first) {
  print(first);
  putchar(' ');
}
template <class T1, class T2>
inline void print(T1 x1, T2 x2) {
  printsp(x1), println(x2);
}
template <class T1, class T2, class T3>
inline void print(T1 x1, T2 x2, T3 x3) {
  printsp(x1), printsp(x2), println(x3);
}
template <class T1, class T2, class T3, class T4>
inline void print(T1 x1, T2 x2, T3 x3, T4 x4) {
  printsp(x1), printsp(x2), printsp(x3), println(x4);
}
int power(int a, int b, int m, int ans = 1) {
  for (; b; b >>= 1, a = (long long)a * a % m)
    if (b & 1) ans = (long long)ans * a % m;
  return ans;
}
vector<int> adj[1001000], a[1001000];
int pa[1001000], dp[1001000], mx;
void dfs(int u) {
  smax(mx, dp[u]);
  if (adj[u].size() == 1) a[dp[u]].push_back(u);
  for (int i = adj[u].size(); i--;) {
    int v = adj[u][i];
    if (v != pa[u]) {
      pa[v] = u;
      dp[v] = dp[u] + 1;
      dfs(v);
    }
  }
}
int root[1001000], len[1001000];
int find_root(int u) {
  if (u == root[u]) return u;
  return root[u] = find_root(root[u]);
}
bool cmp(int u, int v) { return len[u] > len[v]; }
int main() {
  int n, k;
  gn(n, k);
  for (int i = 1, u, v; i < n; i++) {
    gn(u, v);
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  for (int i = 1; i <= n; i++)
    if (adj[i].size() > 1) {
      dp[i] = 1;
      dfs(i);
      break;
    }
  for (int i = 1; i <= n; i++) root[i] = i;
  for (int i = mx; i >= 1; i--) {
    sort(a[i].begin(), a[i].end(), cmp);
    a[i].resize(unique(a[i].begin(), a[i].end()) - a[i].begin());
    for (int j = a[i].size(); j--;) {
      int u = a[i][j], fa = pa[u];
      if (len[fa] + len[u] + 1 <= k) {
        root[u] = fa;
        smax(len[fa], len[u] + 1);
        a[dp[fa]].push_back(fa);
      }
    }
  }
  set<int> s;
  for (int i = 1; i <= n; i++)
    if (adj[i].size() == 1) {
      s.insert(find_root(i));
    }
  println(s.size());
}
