#include <bits/stdc++.h>

using namespace std;

#define pb(x) push_back(x)

#define ll long long

#define mk(x, y) make_pair(x, y)

#define lson l, m, rt<<1

#define mem(a) memset(a, 0, sizeof(a))

#define rson m+1, r, rt<<1|1

#define mem1(a) memset(a, -1, sizeof(a))

#define mem2(a) memset(a, 0x3f, sizeof(a))

#define rep(i, n, a) for(int i = a; i<n; i++)

#define fi first

#define se second

typedef complex <double> cmx;

typedef pair<int, int> pll;

const double PI = acos(-1.0);

const double eps = 1e-;

const int mod = 1e9+;

const int inf = ;

const int dir[][] = { {-, }, {, }, {, -}, {, } };

const int maxn = 1e5+;

int head[maxn], num, mx1[maxn], mx2[maxn], n, maxx, p;

struct node

{

    int to, nextt, val;

}e[maxn*];

void add(int u, int v, int val) {

    e[num].to = v, e[num].nextt = head[u], e[num].val = val, head[u] = num++;

}

void init() {

    num = ;

    mem1(head);

}

int dfs(int u, int fa)

{

    int maxx1 = , maxx2 = ;

    for(int i = head[u]; ~i; i = e[i].nextt) {

        int v = e[i].to;

        if(v == fa)

            continue;

        int tmp = e[i].val + dfs(v, u);

        if(tmp > maxx1) {

            maxx2 = maxx1;

            maxx1 = tmp;

            mx2[u] = mx1[u];

            mx1[u] = i;

        } else if(tmp > maxx2) {

            maxx2 = tmp;

            mx2[u] = i;

        }

    }

    if(maxx < maxx1 + maxx2) {

        maxx = maxx1+maxx2;

        p = u;

    }

    return maxx1;

}

int main()

{

    int k, u, v;

    cin>>n>>k;

    init();

    for(int i = ; i < n - ; i ++) {

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

        add(u, v, );

        add(v, u, );

    }

    dfs(, );

    int ans = *(n-);

    ans -= (maxx - );

    if(k == ) {

        for(int i = mx1[p]; i; i = mx1[e[i].to]) e[i].val = e[i^].val = -;

        for(int i = mx2[p]; i; i = mx1[e[i].to]) e[i].val = e[i^].val = -;

        maxx = ;

        dfs(, );

        ans -= (maxx-);

    }

    cout<<ans<<endl;

    return ;

}