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code: 

#include <cstdio>  
#include <string>
#include <cstring>
#include <algorithm>                   

using namespace std;  

const int N=200006; 

int cur_id; 

namespace IO {  
    void setIO(string s) 
    {
        string in=s+".in"; 
        string out=s+".out"; 
        freopen(in.c_str(),"r",stdin); 
        // freopen(out.c_str(),"w",stdout); 
    }  
}; 

namespace BIT {    
    int C[N];
    #define lowbit(t) (t&(-t))         
    void update(int x,int v) 
    {
        for(int i=x;i<N;i+=lowbit(i)) 
            C[i]+=v; 
    }   
    int query(int x) 
    {
        int tmp=0; 
        for(int i=x;i>0;i-=lowbit(i)) 
            tmp+=C[i];  
        return tmp;   
    }
}; 

namespace LCT {      

    #define lson t[x].ch[0] 
    #define rson t[x].ch[1]      
    #define get(x) (t[t[x].f].ch[1]==x)   
    #define Isrt(x)(!(t[t[x].f].ch[0]==x||t[t[x].f].ch[1]==x))             

    struct node {
        int ch[2],rev,f,size,id;             
    }t[N];           
    int sta[N];         

    void Pushup(int x) 
    { 
        t[x].size=t[lson].size+t[rson].size+1; 
    }    

    void mark(int x) 
    { 
        t[x].rev^=1; 
        swap(lson,rson);  
    }

    void Pushdown(int x) 
    {   
        if(t[x].rev) 
        {
            t[x].rev=0; 
            if(lson)  mark(lson); 
            if(rson)  mark(rson); 
        }    
        if(lson) t[lson].id=t[x].id; 
        if(rson) t[rson].id=t[x].id;   
    }                 

    void Rotate(int x) 
    {
        int old=t[x].f; 
        int fold=t[old].f; 
        int which=get(x);       
        if(!Isrt(old)) 
            t[fold].ch[t[fold].ch[1]==old]=x;        
        t[old].ch[which]=t[x].ch[which^1]; 
        t[t[old].ch[which]].f=old; 
        t[x].ch[which^1]=old; 
        t[old].f=x; 
        t[x].f=fold; 
        Pushup(old); 
        Pushup(x); 
    }
            
    void Splay(int x) 
    {
        int v=0,u=x,fa; 
        for(sta[++v]=u;!Isrt(u);u=t[u].f)  sta[++v]=t[u].f;   
        for(;v;--v) Pushdown(sta[v]);    
        for(u=t[u].f;(fa=t[x].f)!=u;Rotate(x))  
        {
            if(t[fa].f!=u) 
                Rotate(get(fa)==get(x)?fa:x); 
        }
    }       

    void Access(int x) 
    { 
        for(int y=0;x;y=x,x=t[x].f)  
        {
            Splay(x);   
            rson=0; 
            Pushup(x);     
            BIT::update(t[x].id,-t[x].size);            
            BIT::update(cur_id,t[x].size);       
            rson=y; 
            Pushup(x); 
        }
    }

    void Move_Root(int x) 
    {
        ++cur_id;         
        Access(x),Splay(x),mark(x);  
        t[x].id=cur_id;   
    }   

}; 

int n,edges;   
int hd[N],to[N<<1],nex[N<<1];   

int query(int x) 
{  
    using namespace LCT; 
    Splay(x); 
    return BIT::query(t[x].id)-t[lson].size;         
} 

void add(int u,int v) 
{
    nex[++edges]=hd[u],hd[u]=edges,to[edges]=v;   
}      

void dfs(int u,int ff) 
{ 

} 

int main() 
{  
    IO::setIO("input");    
    int i,j;      

    return 0; 
}