#include <cstring>
#include <cstdio>
#include <algorithm>
#include <iostream>
#include <queue>

using namespace std;

const int N = 100010,M = 2 * N;

int h[N],e[M],ne[M],w[M],idx;
int n, k;
int s, p;
int dist[N],father[N];
int d[N];

void add(int a,int b,int c){
    e[idx] = b,w[idx] = c,ne[idx] = h[a],h[a] = idx ++ ;
}

int bfs(int u){
    memset(dist,0x3f,sizeof dist);
    father[u] = -1;
    dist[u] = 0;
    queue<int> q;
    q.push(u);
    while(q.size()){
        auto t = q.front();
        q.pop();
        for(int i = h[t];~i;i = ne[i]){
            int j = e[i];
            if(dist[j] == 0x3f3f3f3f){
                dist[j] = dist[t] + w[i];
                father[j] = i;
                q.push(j);
            }
        }
    }

    int x, y;
    for(x = 1,y = 1;x <= n;x ++)
        if(dist[x] > dist[y]) y = x;
    return y;
}

int ans = 0;
int dp(int u,int fa){
    for(int i = h[u];~i;i = ne[i]){
        int j = e[i];
        if(j == fa) continue;
        dp(j,u);
        ans = max(ans,d[u] + d[j] + w[i]);
        d[u] = max(d[u],d[j] + w[i]);
    }
    return ans;
}
void change(){
    for( ; father[p] != -1;p = e[father[p] ^ 1]) w[father[p]] = w[father[p] ^ 1] = -1;
}
int get(){
    s = bfs(1);
    p = bfs(s);
    return dist[p];
}
int main(){

    memset(h,-1,sizeof h);
    scanf("%d%d",&n,&k);
    for(int i = 1;i < n; i++){
        int a, b;
        scanf("%d%d",&a,&b);
        add(a,b,1),add(b,a,1);
    }

    int l1 = get();
    if(k == 1) cout << 2 * (n - 1) - l1 + 1 << endl;
    else{
        change();
        int l2 = dp(1,0);
        cout << 2 * (n - 1) - l1 - l2 + 2;
    }
    return 0;
}