#include <bits/stdc++.h>
using namespace std;

#define rng(i,a,b) for(int i=int(a);i<int(b);i++)
#define rep(i,b) rng(i,0,b)
#define repn(i,b) rng(i,1,b+1)
#define pb push_back

template<class t>using vc=vector<t>;
using vi=vc<int>;

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

const int inf=INT_MAX/2-100;

int n,k,ans;
vc<int>edge[100005];
int dfs(int v,int u){
	priority_queue<int>que;
	for(auto to:edge[v]){
		if(to==u)continue;
		que.push(dfs(to,v)+1);
	}
	while(que.size() >= 2){
		int x = que.top();que.pop();
		int y = que.top();
		if(x+y > k) {
			ans++;
			continue;
		}
		else{
			que.push(x); break;
		}
	}
	if(que.empty()) return 0;
	else if(que.top() >= k){
		if(v != 1) ans++;
		return 0;
	}
	else return que.top();
}
void slv(){
	cin>>n>>k;
	k<<=1;
	rep(i,n-1){
		int u,v;cin>>u>>v;
		edge[v].pb(u);
		edge[u].pb(v);
	}
	dfs(1, -1);
	cout<<ans+1<<endl;
}

signed main(){
	cin.tie(0);
	ios::sync_with_stdio(0);
	slv();
}