#include<map>#include<stack>#include<queue>#include<cstdio>#include<string>#include<vector>#include<cstring>#include<complex>#include<iostream>#include<assert.h>#include<algorithm>using namespace std;#define inf 1001001001#define infll 1001001001001001001LL#define ll long long#define dbg(vari) cerr<<#vari<<" = "<<(vari)<<endl#define gmax(a,b) (a)=max((a),(b))#define gmin(a,b) (a)=min((a),(b))#define Ri register int#define gc getchar()#define il inlineil int read(){    bool f=true;Ri x=0;char ch;while(!isdigit(ch=gc))if(ch==‘-‘)f=false;while(isdigit(ch)){x=(x<<1)+(x<<3)+ch-‘0‘;ch=gc;}return f?x:-x;}#define gi read()#define FO(x) freopen(#x".in","r",stdin),freopen(#x".out","w",stdout);struct edge{    int to,next;}e[233333];int last[100005],ecnt,cnt,n,k,lb,rb,mid,ans;int f[100005],_a,a[100005];int dfs(int x,int fa=0){    f[x]=0;    //...    for(int i=last[x];i;i=e[i].next)if(e[i].to!=fa)dfs(e[i].to,x);    _a=a[0]=0;    for(int i=last[x];i;i=e[i].next)if(e[i].to!=fa)a[++_a]=f[e[i].to]+1;    sort(a+1,a+_a+1);    while(_a&&a[_a]+a[_a-1]>mid)_a--,ans++;    f[x]=a[_a];}bool chk(){    ans=0;    dfs(1);    return ans<=k;}int main(){    n=gi;k=gi;    for(int i=1;i<n;i++){        int a=gi,b=gi;        e[++ecnt]=(edge){b,last[a]};last[a]=ecnt;        e[++ecnt]=(edge){a,last[b]};last[b]=ecnt;            }    int ans=n,lb=1,rb=n;    while(lb<=rb){        mid=(lb+rb)/2;        if(chk()){            ans=mid;            rb=mid-1;        }else{            lb=mid+1;        }    }    printf("%d",ans);    return 0;}