Bairro

#include <bits/stdc++.h>
using namespace std;

#define MAXN 212345
#define inf 0x3f3f3f3f
typedef pair<int,int> pii;

vector<int> graph[MAXN];
int n, k, maxh, num;
int ans[MAXN], sz[MAXN], hsum[MAXN], subtree_hsum[MAXN];
bool block[MAXN];

int dfs1(int a, int p)
{
        sz[a] = 1;
        for(int i = 0; i < graph[a].size(); i++)
                if(graph[a][i] != p && !block[graph[a][i]])
                        sz[a] += dfs1(graph[a][i], a);
        return sz[a];
}

void dfs2(int a, int p, pii &res)
{
        int mx = num - sz[a];
        for(int i = 0; i < graph[a].size(); i++)
                if(graph[a][i] != p && !block[graph[a][i]])
                {
                        mx = max(mx, sz[graph[a][i]]);
                        dfs2(graph[a][i], a, res);
                }
        if(mx < res.first)
                res = pii(mx, a);
}

int find_centroid(int a)
{
        num = dfs1(a, a);
        pair<int,int> res(inf, 0);
        dfs2(a, a, res);
        return res.second;
}

void dfs3(int a, int p, int h, int vec[])
{
        maxh = max(h, maxh);
        vec[h]++;
        for(int i = 0; i < graph[a].size(); i++)
                if(graph[a][i] != p && !block[graph[a][i]])
                        dfs3(graph[a][i], a, h+1, vec);
}

void dfs4(int a, int p, int h)
{
        if(h > k)
                return;
        ans[a] += hsum[min(num, k - h)] - subtree_hsum[min(maxh, k - h)];
        for(int i = 0; i < graph[a].size(); i++)
                if(graph[a][i] != p && !block[graph[a][i]])
                        dfs4(graph[a][i], a, h+1);
}

void decomp(int a)
{
        a = find_centroid(a);
        maxh = 0;
        num = dfs1(a, a);
        memset(hsum, 0, sizeof(int) * (num + 1));
        dfs3(a, a, 0, hsum);
        for(int i = 1; i <= num; i++)
                hsum[i] += hsum[i-1];
        ans[a] += hsum[min(num, k)];

        for(int i = 0; i < graph[a].size(); i++)
                if(!block[graph[a][i]])
                {
                        memset(subtree_hsum, 0, sizeof(int) * (sz[graph[a][i]] + 1));
                        maxh = 0;
                        dfs3(graph[a][i], a, 1, subtree_hsum);
                        for(int j = 1; j <= maxh; j++)
                                subtree_hsum[j] += subtree_hsum[j-1];
                        dfs4(graph[a][i], a, 1);
                }

        block[a] = true;
        for(int i = 0; i < graph[a].size(); i++)
                if(!block[graph[a][i]])
                        decomp(graph[a][i]);
}

int main(void)
{
        int a, b;
        scanf("%d %d", &n, &k);
        for(int i = 1; i < n; i++)
        {
                scanf("%d %d", &a, &b);
                graph[a].push_back(n+i);
                graph[n+i].push_back(b);
                graph[b].push_back(n+i);
                graph[n+i].push_back(a);
        }
        decomp(1);
        int retv = 0;
        if(k%2 == 0)
                for(int i = 1; i <= n; i++)
                        retv = max(retv, ans[i]);
        else
                for(int i = n+1; i < 2*n; i++)
                        retv = max(retv, ans[i]);
        printf("%d\n", (retv + 1) / 2);
}