互关 门

#include <bits/stdc++.h>
using namespace std;
int n, d, ans;
bool vis[100005];
vector <int> a[100005];
void dfs(int now, int dis){
    vis[now] = 1;
    if (dis == d) return;
    for (int i = 1; i < int(a[now].size()); i++){
        if (!vis[a[now][i]]){
            dfs(a[now][i], dis + 1);
            ans++;
        }
    }
    return;
}
int main(){
    cin >> n >> d;
    for (int i = 1; i < n; i++){
        int u, v;
        cin >> u >> v;
        a[u].push_back(v);
        a[v].push_back(u);
    }
    dfs(1, 0);
    cout << ans;
    return 0;
}