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| #include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdio>
#include<ctype.h>
#define R register
using namespace std;
inline int read()
{
int x=0,w=0;char c=getchar();
while(!isdigit(c))w|=c=='-',c=getchar();
while(isdigit(c))x=(x<<3)+(x<<1)+(c^48),c=getchar();
return w?-x:x;
}
const int maxn=233333;
int n,m,ans[maxn];
int top[maxn],fa[maxn][18],dep[maxn],head[maxn],ecnt,cnt;
struct Edge{
int to,nxt;
}e[maxn<<1];
inline void addedge(int a,int b)
{
e[++ecnt]=(Edge){b,head[a]};head[a]=ecnt;
e[++ecnt]=(Edge){a,head[b]};head[b]=ecnt;
}
bool vis[maxn];
void dfs1(int x,int depth)
{
for (R int i=0;fa[x][i];++i) fa[x][i+1]=fa[fa[x][i]][i];
vis[x]=1;
dep[x]=depth;
for(R int i=head[x];i;i=e[i].nxt)
{
int u=e[i].to;
if(vis[u])continue;
fa[u][0]=x;
dfs1(u,depth+1);
}
}
inline int LCA(int u,int v)
{
if(dep[u]<dep[v])swap(u,v);
for(R int i=0;i<=16;i++)
if((dep[u]-dep[v])&(1<<i))u=fa[u][i];
if(u==v)return u;
for(R int i=16;i>=0;i--)
if(fa[u][i]!=fa[v][i])u=fa[u][i],v=fa[v][i];
return fa[u][0];
}
int Ans=0;
void dfs2(int x)
{
vis[x]=1;
for(R int i=head[x];i;i=e[i].nxt)
{
int u=e[i].to;
if(vis[u])continue;
dfs2(u);
ans[x]+=ans[u];
}
Ans=max(Ans,ans[x]);
}
int main()
{
n=read(),m=read();
for(R int i=1;i<n;i++)addedge(read(),read());
fa[1][0]=0;
dfs1(1,1);
for(R int i=1;i<=m;i++)
{
int x=read(),y=read();
int lca=LCA(x,y);
ans[x]++,ans[y]++,ans[lca]--,ans[fa[lca][0]]--;
}
memset(vis,0,sizeof vis);
dfs2(1);
printf("%d\n",Ans);
return 0;
}
|
