#include<bits/stdc++.h>

using namespace std;

#define MAXN 100010

int i,n,l1,l2,tot,u,v,k,now;

int head[MAXN],pre[MAXN],d[MAXN];

vector< int > path;

pair< int,pair<int,int> > tmp;

struct edge

{

        int to,w,nxt;

} e[MAXN << ];

inline void addedge(int u,int v,int w)

{

        tot++;

        e[tot] = (edge){v,w,head[u]};

        head[u] = tot;

}

inline void dfs1(int u,int fa)

{

        int i,v,w;

        for (i = head[u]; i; i = e[i].nxt)

        {

                v = e[i].to;

                w = e[i].w;

                if (v == fa) continue;

                dfs1(v,u);

                if (d[u] + d[v] + w  > l1)

                {

                        l1 = d[u] + d[v] + w;

                        tmp = make_pair(i,make_pair(pre[u],pre[v]));

                }

                if (d[v] + w > d[u])

                {

                        d[u] = d[v] + w;

                        pre[u] = i;

                }

        }

}

inline void dfs2(int u,int fa)

{

        int i,v,w;

        for (i = head[u]; i; i = e[i].nxt)

        {

                v = e[i].to;

                w = e[i].w;

                if (v == fa) continue;

                dfs2(v,u);

                if (d[u] + d[v] + w > l2) l2 = d[u] + d[v] + w;

                d[u] = max(d[u],d[v] + w);

        }

}

int main()

{

        scanf("%d%d",&n,&k);

        for (i = ; i < n; i++)

        {

                scanf("%d%d",&u,&v);

                addedge(u,v,);

                addedge(v,u,);

        }

        l1 = ;

        memset(d,,sizeof(d));

        dfs1(,);

        now = tmp.second.first;

        while (now != )

        {

                path.push_back(now);

                now = pre[e[now].to];

        }

        path.push_back(tmp.first);

        now = tmp.second.second;

        while (now != )

        {

                path.push_back(now);

                now = pre[e[now].to];

        }

        for (i = ; i < path.size(); i++)

        {

                e[path[i]].w *= -;

                e[path[i] ^ ].w *= -;

        }

        l2 = ;

        memset(d,,sizeof(d));

        dfs2(,);

        if (k == ) printf("%d\n", * (n - ) - l1 + );

        else printf("%d\n", * n - l1 - l2);

        return ;

}