//存储结构

 struct node

 {

     int data;

     int height; //记录当前子树的高度(叶子->根)

                 //存储平衡因子的话，无法通过其子树算得该树的平衡因子

     node *lchild, *rchild;

 };

 //新建结点

 node *newNode(int v)

 {

     node *root = new node;

     root->data = v;

     root->height = ;

     root->lchild = root->rchild = NULL;

     return root;

 }

 //获取当前结点所在高度

 int GetHeight(node *root)

 {

     if(root == NULL)

         return ;

     return root->height;

 }

 //计算结点的平衡因子

 int GetBalanceFactors(node *root)

 {

     return GetHeight(root->lchild)-GetHeight(root->rchild);

 }

 //更新结点高度

 void UpdataHeight(node *root)

 {

     root->height = max(GetHeight(root->lchild), GetHeight(root->rchild))+;

 }

 //查找

 void Search(node *root, int x)

 {

     if(root == NULL)

         return;

     if(x == root->data)

         //visit

     else if(x < root->data)

         Search(root->lchild, x);

     else

         Search(root->rchild, x);

 }

 //左右旋互为逆操作

 //左旋

 void LeftRotation(node *&root)

 {

     node *temp = root->lchild;      //temp指向新的根结点B

     root->rchild = temp->lchild;    //B的左子树给A的右子树

     temp->lchild = root;            //B的左子树变为A

     UpdataHeight(root);             //更新结点高度

     UpdataHeight(temp);

     root = temp;                    //令B成为新的根结点

 }

 //右旋

 void RightRotation(node *&root)

 {

     node *temp = root->lchild;

     root->lchild = temp->rchild;

     temp->rchild = root;

     UpdataHeight(root);

     UpdataHeight(temp);

     root = temp;

 }

 /*

 1.LL: A==+2, A->lchild=+1

     A作为root进行右旋

 2.LR: A==+2, A->lchild=-1

     A->lchild作为root进行左旋 --> 转化为LL

     A作为root进行右旋

 3.RR: A==-2, A->rchild=-1

     A作为root进行左旋

 4.RL: A==-2, A->rchild=+1

     A->rchild作为root进行右旋 --> 转化为RR

     A作为root进行左旋

 */

 //插入

 void Insert(node *&root, int v)

 {

     if(root == NULL)

     {

         root = newNode(v);

         return;

     }

     if(v < root->data)

     {

         Insert(root->lchild, v);

         UpdataHeight(root);     //更新树高

         if(GetBalanceFactor(root) == )

         {

             if(GetBalanceFactor(root->lchild) == )

                 RightRotation(root);

             else

             {

                 LeftRotation(root->lchild);

                 RightRotation(root);

             }

         }

     }

     else

     {

         Insert(root->rchild, v);

         UpdataHeight(root);

         if(GetBalanceFactor(root) == -)

         {

             if(GetBalanceFactor(root->rchild) == -)

                 LeftRotation(root);

             else

             {

                 RightRotation(root->rchild);

                 LeftRotation(root);

             }

         }

     }

 }

 //建立

 node *Create(int data[], int n)

 {

     node *root = NULL;

     for(int i=; i<n; i++)

         Insert(root, data[i]);

     return root;

 }

 #include <cstdio>

 const int M = ;

 int pre[M]={,,,,,,,,,};

 int in[M]={,,,,,,,,,};

 struct node

 {

     int data;

     node *lchild, *rchild;

 };

 node *Create(int preL, int preR, int inL, int inR)

 {

     if(preL > preR)

         return NULL;

     node *root = new node;

     root->data = pre[preL];

     int k;

     for(k=inL; k<=inR; k++)

         if(in[k] == root->data)

             break;

     int numLeft = k-inL;

     root->lchild = Create(preL+, preL+numLeft, inL, k-);

     root->rchild = Create(preL+numLeft+, preR, k+, inR);

 }

 int IsAvl = true;

 int IsAVL(node *root)

 {

     if(root == NULL)

         return -;

     int bl = IsAVL(root->lchild)+;

     int br = IsAVL(root->rchild)+;

     if(bl-br> || bl-br<-)

         IsAvl = false;

     return bl>br?bl:br;

 }

 int main()

 {

 #ifdef    ONLINE_JUDGE

 #else

     freopen("Test.txt", "r", stdin);

 #endif

     node *root = Create(,M-,,M-);

     IsAVL(root);

     if(IsAvl)

         printf("Yes.");

     else

         printf("No.");

     return ;

 }