#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#define N 2000005
#define int long long
#define ul unsigned long long
#define db double
#define fo(i,l,r) for(int i=l;i<=r;i++)
#define rf(i,r,l) for(int i=r;i>=l;i--)
using namespace std;
int n,k,h[N],cnt=1,d[N],p[N],f[N],s=1,x,y,ans;
struct edge{int v,n,w;}e[N<<1];
void ad(int u,int v,int w){e[++cnt]={v,h[u],w};h[u]=cnt;}
void swap(int &x,int &y){int t=x;x=y;y=t;}
int max(int x,int y){return x>y?x:y;}
int min(int x,int y){return x<y?x:y;}
void dfs1(int u,int f)
{
	p[u]=f;
	if(d[u]>d[s])s=u;
	for(int i=h[u];i;i=e[i].n)
	{
		if(i==f)continue;
		int v=e[i].v,w=e[i].w;
		d[v]=d[u]+w;dfs1(v,i^1);
	}
}
void dfs2(int u,int fa)
{
	for(int i=h[u];i;i=e[i].n)
	{
		int v=e[i].v,w=e[i].w;
		if(v==fa)continue;
		dfs2(v,u);
		x=max(x,f[u]+f[v]+w);
		f[u]=max(f[u],f[v]+w);
	}
}
int read(){
	int sum=0;bool f=0;char c=getchar();
	for(;c<48||c>57;c=getchar())if(c==45)f=1;
	for(;c>=48&&c<=57;c=getchar())sum=sum*10+(c&15);
	return f?-sum:sum;
}
signed main(){
	freopen("xunluo.in","r",stdin);freopen("xunluo.out","w",stdout);
	n=read();k=read();ans=2*n-2;
	fo(i,1,n-1)x=read(),y=read(),ad(x,y,1),ad(y,x,1);
	dfs1(s,0);d[s]=0;dfs1(s,0);
	while(p[s])
	{
		ans--;
		e[p[s]].w=e[p[s]^1].w=-1;
		s=e[p[s]].v;
	}
	ans++;
	if(k==1)return !printf("%lld",ans);
	x=0;dfs2(1,0);
	ans-=x-1;
	printf("%lld",ans);
	return 0;
}