求大神指教，深搜前4个点超时了

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
vector<int> G[N];
int n, m, ans, d, dis[N];
void addedge(int u, int v) {
    G[u].push_back(v);
    G[v].push_back(u);
}
void dfs(int u, int f) {
    if(dis[u] <= d) ans++;
    for(int i = 0; i < G[u].size(); i++) {
        int v = G[u][i];
        if(v == f) continue;
        dis[v] = dis[u] + 1;
        dfs(u, v);
    }
}
int main() {
    scanf("%d%d", &n, &d);
    for(int i = 1; i < n; i++) {
        int u, v;
        scanf("%d%d", &u, &v);
        addedge(u, v);
    }
    dfs(1, 0);
    printf("%d\n", ans - 1);
}