这才是真正的A+Bproblem

#include<assert.h>
//#include<bits/stdc++.h>
#include<ctype.h>
#include<cstring>
#include<errno.h>
#include<float.h>
#include<fstream>
#include<iomanip>
#include<iostream>
#include<limits.h>
#include<locale.h>
#include<math.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
//#include<strstrea>
#include<time.h>
#include<wchar.h>
#include<wctype.h>
#include<algorithm>
#include<bitset>
#include<cctype>
#include<cerrno>
#include<clocale>
#include<cmath>
#include<complex>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<ctime>
#include<deque>
#include<exception>
#include<fstream>
#include<functional>
#include<limits>
#include<list>
#include<map>
#include<iomanip>
#include<ios>
#include<iosfwd>
#include<iostream>
#include<istream>
#include<ostream>
#include<queue>
#include<set>
#include<sstream>
#include<stack>
#include<stdexcept>
#include<streambuf>
#include<string>
#include<utility>
#include<vector>
#include<cwchar>
#include<cwctype>
#include<complex.h>
#include<fenv.h>
#include<inttypes.h>
#include<stdbool.h>
#include<stdint.h>
#include<tgmath.h>
using namespace std;
struct node{
    int data,rev,sum;
    node *son[2],*pre;
    bool judge();
    bool isroot();
    void pushdown();
    void update();
    void setson(node *child,int lr);
};
node lct[233];
int top;
int a_a1s;
int b_b1s;
node *getnew(int x)
{
    node *now = lct+ ++top;
    now->data = x;
    now->pre = now->son[1] = now->son[0] = lct;
    now->sum = 0;
    now->rev = 0;
    return now;
}
bool node::judge()
{
	return pre->son[1] == this;
}
bool node::isroot()
{
    if(pre == lct)
	{
    	return true;
	}
    return !(pre->son[1] == this || pre->son[0] == this);
}
void node::pushdown()
{
    if(this == lct || !rev)
	{
    	return ;
	}
    swap(son[0],son[1]);
    son[0]->rev ^= 1;
    son[1]->rev ^= 1;
    rev = 0;
}
void node::update()
{
	sum = son[1]->sum + son[0]->sum + data;
}
void node::setson(node *child,int lr)
{
    this->pushdown();
    child->pre = this;
    son[lr] = child;
    this->update();
}
void rotate(node *now)
{
    node *father = now->pre,*grandfa = father->pre;
    if(!father->isroot())
	{
    	grandfa->pushdown();
	}
    father->pushdown();
	now->pushdown();
    int lr = now->judge();
    father->setson(now->son[lr^1],lr);
    if(father->isroot())
	{
    	now->pre = grandfa;
	}
    else
	{
    	grandfa->setson(now,father->judge());
	}
    now->setson(father,lr^1);
    father->update();now->update();
    if(grandfa != lct)
	{
    	grandfa->update();
	}
}
void splay(node *now)
{
    if(now->isroot())
	{
    	return ;
	}
    for(;!now->isroot();rotate(now))
	{
    	if(!now->pre->isroot())
		{
    		now->judge() == now->pre->judge()?rotate(now->pre):rotate(now);
		}
	}
}
node *access(node *now)
{
    node *last = lct;
    for(;now != lct;last = now,now = now->pre)
	{
        splay(now);
        now->setson(last,1);
    }
    return last;
}
void changeroot(node *now)
{
    access(now)->rev ^= 1;
    splay(now);
}
void connect(node *x,node *y)
{
    changeroot(x);
    x->pre = y;
    access(x);
}
void cut(node *x,node *y)
{
    changeroot(x);
    access(y);
    splay(x);
    x->pushdown();
    x->son[1] = y->pre = lct;
    x->update();
}
int query_query19(node *x,node *y)
{
    changeroot(x);
    node *now = access(y);
    return now->sum;
}
int main()
{
    cin>>a_a1s>>b_b1s;
    node *A=getnew(a_a1s);
    node *B=getnew(b_b1s);
    connect(A,B);
    cut(A,B);
    connect(A,B);
    cout<<query_query19(A,B);
    return 0;
}

区区亿点点而已啦