typedef int QDataType;
typedef struct QueueNode
{
  struct QueueNode* next;
  QDataType data;
}QNode;
typedef struct Queue
{
  QNode* phead;
  QNode* ptail;
  int size;
}Queue;
void QueueInit(Queue* pq);
void QueueDestroy(Queue* pq);
void QueuePush(Queue* pq, QDataType x);
void QueuePop(Queue* pq);
QDataType QueueFront(Queue* pq);
QDataType QueueBack(Queue* pq);
int QueueSize(Queue* pq);
bool QueueEmpty(Queue* pq);
void QueueInit(Queue* pq)
{
  assert(pq);
  pq->phead = NULL;
  pq->ptail = NULL;
  pq->size = 0;
}
void QueueDestroy(Queue* pq)
{
  assert(pq);
  QNode* cur = pq->phead;
  while (cur)
  {
  QNode* next = cur->next;
  free(cur);
  cur = next;
  }
  pq->phead = pq->ptail = NULL;
  pq->size = 0;
}
void QueuePush(Queue* pq, QDataType x)
{
  assert(pq);
  QNode* newnode = (QNode*)malloc(sizeof(QNode));
  if (newnode == NULL)
  {
  perror("malloc fail\n");
  return;
  }
  newnode->data = x;
  newnode->next = NULL;
  if (pq->ptail == NULL)
  {
  assert(pq->phead == NULL);
  pq->phead = pq->ptail = newnode;
  }
  else
  {
  pq->ptail->next = newnode;
  pq->ptail = newnode;
  }
  pq->size++;
}
void QueuePop(Queue* pq)
{
  assert(pq);
  assert(!QueueEmpty(pq));
  if (pq->phead->next == NULL)
  {
  QNode* head = pq->phead;
  free(head);
  pq->phead = pq->ptail = NULL;
  pq->size = 0;
  }
  else
  {
  QNode* head = pq->phead;
  pq->phead = pq->phead->next;
  free(head);
  pq->size--;
  }
}
QDataType QueueFront(Queue* pq)
{
  assert(pq);
  assert(!QueueEmpty(pq));
  return(pq->phead->data);
}
QDataType QueueBack(Queue* pq)
{
  assert(pq);
  assert(!QueueEmpty(pq));
  return pq->ptail->data;
}
int QueueSize(Queue* pq)
{
  assert(pq);
  return pq->size;
}
bool QueueEmpty(Queue* pq)
{
  assert(pq);
  return pq->size == 0;
}
typedef struct {
    Queue q1;
    Queue q2;
} MyStack;
MyStack* myStackCreate() {
    MyStack* tmp = (MyStack*)malloc(sizeof(MyStack));
    if(tmp==NULL)
    {
        perror("malloc fail");
        return NULL;
    }
    QueueInit(&(tmp->q1));
    QueueInit(&(tmp->q2));
    return tmp;
}
void myStackPush(MyStack* obj, int x) {
    if(!QueueEmpty(&obj->q1)){
        QueuePush(&obj->q1, x);
    }
    else{
        QueuePush(&obj->q2, x);
    }
}
int myStackPop(MyStack* obj) {
    Queue* empty = &obj->q1;
    Queue* noempty = &obj->q2;
    if(!QueueEmpty(empty))
    {
        empty = &obj->q2;
        noempty=&obj->q1;
    }
    while(QueueSize(noempty)>1)
    {
        QueuePush(empty, QueueFront(noempty));
        QueuePop(noempty);
    }
    int n = QueueFront(noempty);
    QueuePop(noempty);
     return n;
}
int myStackTop(MyStack* obj) {
    if(!QueueEmpty(&obj->q1))
    {
        return QueueBack(&obj->q1);
    }
    else
    {
        return QueueBack(&obj->q2);
    }
}
bool myStackEmpty(MyStack* obj) {
    return QueueEmpty(&obj->q1) && QueueEmpty(&obj->q2);
}
void myStackFree(MyStack* obj) {
    QueueDestroy(&obj->q1);
    QueueDestroy(&obj->q2);
    free(obj);
}
/**
 * Your MyStack struct will be instantiated and called as such:
 * MyStack* obj = myStackCreate();
 * myStackPush(obj, x);
 * int param_2 = myStackPop(obj);
 * int param_3 = myStackTop(obj);
 * bool param_4 = myStackEmpty(obj);
 * myStackFree(obj);
*/