#include <iostream>
#include <iomanip>
#include <cstdio>
#include <vector>
#include <bitset>
#include <string>
#include <cstring>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>
#include <utility>
#include <algorithm>
#include <random>
#include <cmath>
#include <cassert>
#include <climits>
#include <ctime>
#include <chrono>


/*
#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,sse4.1,sse4.2,popcnt,abm,mmx,avx,avx2,tune=native")
*/


#ifdef LOCAL
    #define dbg(x) cout << #x << " : " << x << endl;
#else
    #define dbg(x)
#endif

#define int long long
#define pb push_back
#define ppb pop_back()
#define mp make_pair
#define fi(a, b) for (int i = a; i < b; i++)
#define fj(a, b) for (int j = a; j < b; j++)
#define fk(a, b) for (int k = a; k < b; k++)
#define fi1(a, b) for (int i = a - 1; i >= b; i--)
#define fj1(a, b) for (int j = a - 1; j >= b; j--)
#define fk1(a, b) for (int k = a - 1; k >= b; k--)
#define fx(x, a) for (auto& x : a)
#define rep(i, a, b) for (int i = a; i < b; ++i)
#define rep1(i, a, b) for (int i = a - 1; i >= b; --i)
#define siz(x) (int)x.size()
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

using namespace std;

template<typename T1, typename T2>inline void mine(T1 &x, const T2 &y) { if (y < x) x = y; }
template<typename T1, typename T2>inline void maxe(T1 &x, const T2 &y) { if (x < y) x = y; }

ostream& operator << (ostream &out, const vector<int> &b) {
    for (auto k : b) out << k << ' ';
    return out;
}

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef char ch;
typedef string str;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vpii;
typedef vector<vpii> vvpii;
typedef vector<ch> vch;
typedef vector<vch> vvch;
typedef vector<str> vs;



int MOD = 1000000007;
const int INF = 1000000050;
const long long BIG = (long long)2e18 + 50;
const int MX = 200010;
const double EPS = 1e-9;


mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

ll add(ll a, ll b) {
	a += b;
	if (a >= MOD) return a - MOD;
	return a;
}

ll sub(ll a, ll b) {
	a -= b;
	if (a < 0) return a + MOD;
	return a;
}

ll mult(ll a, ll b) {
	return a * b % MOD;
}

ll powmod(ll a, ll p) {
	if (p == 0) return 1;
	if (p & 1) return mult(a, powmod(a, p - 1));
	return powmod(mult(a, a), p / 2);
}

ll rev(ll a) {
	return powmod(a, MOD - 2);
}
int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n;
    int MOD1;
    cin >> n >> MOD1;
    MOD = MOD1 * MOD1;
    int pw2 = powmod(10, n);
    int pw1 = pw2 % MOD1;
    for (int r = 0; r < MOD1; ++r) {
    	if (mult(r, MOD1) == sub(pw2, pw1)) {
    		cout << r << '\n';
    	}
    }
}

#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define mkp(x,y) make_pair(x,y)
#define pb(x) push_back(x)
#define sz(v) (int)v.size()
typedef long long LL;
typedef double db;
template<class T>bool ckmax(T&x,T y){return x<y?x=y,1:0;}
template<class T>bool ckmin(T&x,T y){return x>y?x=y,1:0;}
#define rep(i,x,y) for(int i=x,i##end=y;i<=i##end;++i)
#define per(i,x,y) for(int i=x,i##end=y;i>=i##end;--i)
inline int read(){
	int x=0,f=1;char ch=getchar();
	while(!isdigit(ch)){if(ch=='-')f=0;ch=getchar();}
	while(isdigit(ch))x=x*10+ch-'0',ch=getchar();
	return f?x:-x;
}
const int N=200005;
const int inf=0x3f3f3f3f;
int n,k,f[N],g[N];
vector<int>e[N];
int num;
void dfs(int u,int ft,int o){
	f[u]=-inf,g[u]=inf;
	for(int v:e[u]){
		if(v==ft)continue;
		dfs(v,u,o);
		ckmax(f[u],f[v]+1);
		ckmin(g[u],g[v]+1);
	}
	if(f[u]+g[u]<=o)f[u]=-inf;
	if(g[u]>o)ckmax(f[u],0);
	if(f[u]==o)++num,f[u]=-inf,g[u]=0;
}
bool check(int mid){
	num=0;
	dfs(1,0,mid);
	if(f[1]>=0)++num;
	return num<=k;
}
signed main(){
	cin>>n>>k;
	rep(i,2,n){
		int x=read(),y=read();
		e[x].pb(y),e[y].pb(x);
	}
	int l=0,r=n,res=n;
	while(l<=r){
		int mid=(l+r)>>1;
		if(check(mid))res=mid,r=mid-1;
		else l=mid+1;
	}
	cout<<res<<'\n';
}