#include<bits/stdc++.h>
#define re register
using namespace std;
inline int read(){
    re int t=0;re char v=getchar();
    while(v<'0')v=getchar();
    while(v>='0')t=(t<<3)+(t<<1)+v-48,v=getchar();
    return t;
}
int t,n,m,head[1000002],mn,pos,siz[1000002],Z,bl[1000002],num[1000002],dis[1000002],cnt,P,S[500002],deg[500002];
char v[1000002];
long long ans;
struct edge{
    int to,next;
}e[1000002];
struct node{
    int x,y;
    bool operator <(const node A)const{return x>A.x;}
}p[500002];
inline void add(re int x,re int y){e[++cnt]=(edge){y,head[x]},head[x]=cnt;}
inline void dfs(re int x,re int y){
    siz[x]=1;re int mx=0;
    for(re int i=head[x];i;i=e[i].next)
        if(!v[e[i].to]&&(e[i].to^y))
            dfs(e[i].to,x),siz[x]+=siz[e[i].to],mx=max(mx,siz[e[i].to]);
    mx=max(mx,Z-siz[x]);
    if(mx<mn)mn=mx,pos=x;
}
inline void dfs1(re int x,re int y,re int z){
    bl[x]=z,dis[x]=dis[y]+1;
    for(re int i=head[x];i;i=e[i].next)
        if(e[i].to^y)
            dfs1(e[i].to,x,z);
}
inline void chk(re int x){
    memset(num,0,sizeof(num));
    re long long s=0;
    bl[x]=x,dis[x]=0;
    for(re int i=head[x];i;i=e[i].next)dfs1(e[i].to,x,e[i].to);
    for(re int i=1;i<=n;++i)p[i]=(node){dis[i],i};
    sort(p+1,p+n+1);
    P=0;int o=1;
    for(re int i=1;i<=m;++i){
        if(num[bl[p[o].y]]==(m>>1)&&P==0)P=bl[p[o].y];
        while(o<=n&&num[bl[p[o].y]]==(m>>1))++o;
        if(o>n){
            s=1e18;
            break;
        }
        s+=(n-1-p[o].x-p[o].x);
        ++num[bl[p[o].y]];++o;
    }
    ans=min(ans,s);
}
inline void dfs2(re int x,re int y){
    for(re int i=head[x];i;i=e[i].next)
        if(e[i].to^y){
            dfs2(e[i].to,x);
            S[x]+=S[e[i].to];
        }
    if(P==0&&S[x]>=(m>>1)+1)P=x;
}
inline void chk1(re int x){
    memset(num,0,sizeof(num));
    re long long s=0;
    bl[x]=x,dis[x]=0;
    for(re int i=head[x];i;i=e[i].next)dfs1(e[i].to,x,e[i].to);
    for(re int i=1;i<=n;++i)p[i]=(node){dis[i],i};
    sort(p+1,p+n+1);
    P=0;int o=1;
    for(re int i=1;i<=m;++i){
    /*    if(num[bl[p[o].y]]==(m>>1)&&P==0){
            memset(S,0,sizeof(S));
            for(re int j=1;j<=o;++j)if(bl[p[o].y]==bl[p[j].y])S[p[j].y]=1;
            dfs2(x,x);	
        }*/
        while(o<=n&&num[bl[p[o].y]]==(m>>1))++o;
        if(o>n){
            s=1e18;
            break;
        }
        s+=(n-1-p[o].x-p[o].x);
        ++num[bl[p[o].y]];++o;
    }
    ans=min(ans,s);
    memset(num,0,sizeof(num));
    o=1;
    for(re int i=1;i<=m;++i){
        ++num[bl[p[o].y]];++o;
    }
    memset(S,0,sizeof(S)),P=0;
    for(re int j=1;j<=m;++j)if(num[bl[p[j].y]]*2>m)S[p[j].y]=1;
    dfs2(x,x);
}
inline void dfz(re int x,re int y){
    Z=y,mn=1e9,dfs(x,x),x=pos,dfs(x,x),v[x]=1;
    chk(x);
    if(P&&!v[P])dfz(P,siz[P]);
}

int main(){ans=1e18;
//freopen("a.in","r",stdin);
    n=read(),m=read();
    if(m==1){
        printf("%d\n",n-1);
        return 0;
    }
    for(re int i=1,x,y;i<n;++i)x=read(),y=read(),add(x,y),add(y,x),++deg[x],++deg[y];
    for(re int i=1;i<=n;++i)if(deg[i]>=deg[P])P=i;
    chk1(P);    
	for(re int i=1;i<=n;++i)if(deg[i]>deg[P])P=i;
    chk1(P);
    mn=1e9,Z=n,dfs(1,1),P=pos;//printf("%d\n",P);
//    dfs3(1,1,0);
//	dfz(1,n);
//printf("%lld\n",ans);
//	re long long tmp=ans;
//	for(re int i=1;i<=n;++i)chk(i);
//	printf("%lld\n",ans);
//	assert(tmp==ans);
    ans=1e18;
    for(re int i=1;i<=15&&P;++i)chk1(P);
    printf("%lld",ans);
}