1 #include <vector>
 2 #include <cstdio>
 3 #include <algorithm>
 4 #include <cstring>
 5 #define ll long long
 6 #define N 1001000
 7 #define uint unsigned int
 8 #define inf 0x3f3f3f3f3f3f3fll
 9 using namespace std;
10 //re
11 int gint()
12 {
13     int ret=0,fh=1;char c=getchar();
14     while(c<'0'||c>'9'){if(c=='-')fh=-1;c=getchar();}
15     while(c>='0'&&c<='9'){ret=(ret<<3)+(ret<<1)+c-'0';c=getchar();}
16     return ret*fh;
17 }
18
19 int n,m,cte,num,S;
20 int head[N],fa[N],inc[N];
21 struct Edge{int to,nxt;}edge[N*2];
22
23 void ae(int u,int v){
24     cte++;edge[cte].to=v,inc[v]++;
25     edge[cte].nxt=head[u],head[u]=cte;
26 }
27
28 vector<int>to[N];
29 int ma[N];
30 int cmp(int x,int y){return ma[x]<ma[y];}
31 int solve(int u){
32     int ans=0,l,r;
33     for(int j=head[u];j;j=edge[j].nxt)
34     {
35         int v=edge[j].to;
36         if(v==fa[u]) continue;
37         to[u].push_back(v);
38         ans+=solve(v);
39     }
40     int tot=to[u].size();
41     sort(to[u].begin(),to[u].end(),cmp);
42     if(!tot){ma[u]=1;return 0;}
43     if(tot==1){ma[u]=ma[to[u][tot-1]];}
44     else if(ma[to[u][tot-1]]+ma[to[u][tot-2]]<=m)
45         ma[u]=ma[to[u][tot-1]];
46     else{
47         l=0,r=tot-1;
48         while(r>0&&l<r&&ma[to[u][r]]+ma[to[u][r-1]]>m){
49             for(;l<r&&ma[to[u][r]]+ma[to[u][l]]<=m;l++);
50             r--,ans++;
51         }ma[u]=ma[to[u][r]];
52     }ma[u]+=(ma[u]>0?1:0);return ans;
53 }
54
55
56 int main()
57 {
58     scanf("%d%d",&n,&m);
59     int x,y;
60     for(int i=1;i<n;i++)
61         x=gint(),y=gint(),ae(x,y),ae(y,x);
62     for(int i=1;i<=n;i++)
63         if(inc[i]!=1) {S=i;break;}
64     dep[S]=1,dfs1(S,-1);
65     tp[S]=1,dfs2(S);
66     int ans=solve(S);
67     if(ma[S]-1>0) ans++;
68     printf("%d\n",ans);
69     return 0;
70 }