样例过了但是0pts

# include <stdio.h>
# include <iostream>
# include <algorithm>
# include <string>
# include <queue>
using namespace std;
int n,d;
struct edge{
	int to,nxt;
}e[114514];
int tot=0;
int head[114514];
bool vis[114514];
int ans=0;
void add(int u,int v){
	e[++tot].to=v;
	e[tot].nxt=head[u];
	head[u]=tot;
	return;
}
void dfs(int pos,int k){
	if(k>=d){
		return;
	}
	for(int i=head[pos];i;i=e[i].nxt){
		int nw=e[i].to;
		if(!vis[nw]){
			ans++;
			vis[nw]=1;
			dfs(nw,k+1);
		}
	}
}
int main(){
	scanf("%d%d",&n,&d);
	for(int i=1;i<n;i++){
		int u,v;scanf("%d%d",&u,&v);
		add(u,v);
		add(v,u);
	}
	dfs(1,0);
	printf("%d",ans);
	return 0;
}