#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <vector>
#include <stack>
#include <map>
#include <set>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <bitset>
#include <assert.h>
#include <unordered_map>

using namespace std;
typedef long long ll;

#define Cmp(a, b) memcmp(a, b, sizeof(b))
#define Cpy(a, b) memcpy(a, b, sizeof(b))
#define Set(a, v) memset(a, v, sizeof(a))
#define debug(x) cout << #x << ": " << x << endl
#define _forS(i, l, r) for(set<int>::iterator i = (l); i != (r); i++)
#define _rep(i, l, r) for(int i = (l); i <= (r); i++)
#define _for(i, l, r) for(int i = (l); i < (r); i++)
#define _forDown(i, l, r) for(int i = (l); i >= r; i--)
#define debug_(ch, i) printf(#ch"[%d]: %d\n", i, ch[i])
#define debug_m(mp, p) printf(#mp"[%d]: %d\n", p->first, p->second)
#define debugS(str) cout << "dbg: " << str << endl;
#define debugArr(arr, x, y) _for(i, 0, x) { _for(j, 0, y) printf("%c", arr[i][j]); printf("\n"); }
#define _forPlus(i, l, d, r) for(int i = (l); i + d < (r); i++)
#define lowbit(i) (i & (-i))
#define MPR(a, b) make_pair(a, b)

pair<int, int> crack(int n) {
    int st = sqrt(n);
    int fac = n / st;
    while (n % st) {
        st += 1;
        fac = n / st;
    }

    return make_pair(st, fac);
}

inline ll qpow(ll a, int n) {
    ll ans = 1;
    for(; n; n >>= 1) {
        if(n & 1) ans *= 1ll * a;
        a *= a;
    }
    return ans;
}

template <class T>
inline bool chmax(T& a, T b) {
    if(a < b) {
        a = b;
        return true;
    }
    return false;
}

ll gcd(ll a, ll b) {
    return b == 0 ? a : gcd(b, a % b);
}

ll ksc(ll a, ll b, ll mod) {
    ll ans = 0;
    for(; b; b >>= 1) {
        if (b & 1) ans = (ans + a) % mod;
        a = (a * 2) % mod;
    }
    return ans;
}

ll ksm(ll a, ll b, ll mod) {
    ll ans = 1 % mod;
    a %= mod;

    for(; b; b >>= 1) {
        if (b & 1) ans = ksc(ans, a, mod);
        a = ksc(a, a, mod);
    }

    return ans;
}

template <class T>
inline bool chmin(T& a, T b) {
    if(a > b) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool lexSmaller(vector<T> a, vector<T> b) {
    int n = a.size(), m = b.size();
    int i;
    for(i = 0; i < n && i < m; i++) {
        if (a[i] < b[i]) return true;
        else if (b[i] < a[i]) return false;
    }
    return (i == n && i < m);
}

// ============================================================== //

const int maxn = 200000 + 10;
int head[maxn], edges[maxn], ver[maxn], ne[maxn], tot = 1;
int n, K;

void add(int x, int y, int z) {
    ver[++tot] = y; edges[tot] = z; ne[tot] = head[x]; head[x] = tot;
}

int vis[maxn], pre[maxn], d[maxn], pos;
void bfs(int u) {
    memset(vis, 0, sizeof vis);
    memset(pre, 0, sizeof pre);
    memset(d, 0, sizeof d);
    vis[u] = 1; d[u] = 0;
    queue<int> q; q.push(u);

    while (!q.empty()) {
        int x = q.front(); q.pop();
        for (int i = head[x]; i; i = ne[i]) {
            int y = ver[i];
            if (vis[y]) continue;
            vis[y] = 1; d[y] = d[x] + edges[i];
            pre[y] = i;
            if (d[pos] < d[y]) pos = y;
            q.push(y);
        }
    }
}

void dp(int x, int &res) {
    vis[x] = 1;
    for (int i = head[x]; i; i = ne[i]) {
        int y = ver[i];
        if (vis[y]) continue;
        dp(y, res);
        res = max(res, d[x] + d[y] + edges[i]);
        d[x] = max(d[x], d[y] + edges[i]);
    }
}

void solve() {
    bfs(1);
    int a = pos;

    bfs(a);
    int ans = 2*(n-1) - (d[pos] - 1);
    if (K == 1) {
        printf("%d\n", ans);
        return;
    }

    // reverse path
    int u = pos;
    while (u) {
        int e = pre[u];
        edges[e] = edges[e^1] = -1;
        u = ver[e^1];
    }

    // dp
    memset(vis, 0, sizeof vis);
    memset(d, 0, sizeof d);
    int L = 0;
    dp(1, L);
    ans -= (L-1);
    printf("%d\n", ans);
}

int main() {
    //freopen("input.txt", "r", stdin);
    scanf("%d%d", &n, &K);
    for (int i = 0; i < n-1; i++) {
        int a, b;
        scanf("%d%d", &a, &b);
        add(a, b, 1);
        add(b, a, 1);
    }

    // then solve
    solve();
}