#include<stdio.h>
#include<malloc.h>
typedef struct ploynode
{
    int date;
    struct ploynode *next;   
} *pnode;
pnode creat()
{
    int m=0;
    int n;
    pnode head,p,s;
    head=(pnode)malloc(sizeof( struct ploynode));
    head->next=NULL;
    p=head;
    scanf("%d",&n);
    while(n!='#')
    {
        s=(pnode)malloc(sizeof( struct ploynode));
        s->date=n;
        s->next=NULL;
        p->next=s;
        p=s;
        m=m+1;
        scanf("%d",&n);
    }
    head->date=m;
    return(head);
}
pnode stack (pnode head)
{
    int i,j;
    pnode top,p;
    j=head->date;
    for(i=1;i<=j/2;j++)
    {
    top=(pnode)malloc(sizeof( struct ploynode));
    p->date=head->date;
    head=head->next;
    p->next=top->next;
    top->next=p;
    }
    return(top);
}
void bj(pnode p1,pnode p2)
{
    int x,y,i;
    x=p1->date;
    y=p1->date%2;
    p1=p1->next;
    p2=p2->next;
    for(i=1;i<=x/2;i++)
    {
        p1=p1->next;
    }
    switch(y)
    {
    case 1:
    p1=p1->next;
    while(p1->next!=NULL)
    {
        if (p1->date==p2->date)
        {p1=p1->next;
        p2=p2->next;}
        else break;
    }
    if(p1->next==NULL)
    printf("ok");
    else printf("error");
    break;
    case 0:
    while(p1->next!=NULL)
    {
        if (p1->date==p2->date)
        {p1=p1->next;
        p2=p2->next;}
        else break;
    }
    if(p1->next==NULL)
    printf("ok");
    else printf("error");
    break;
    default: printf("no");
    }
}
int main()
{
    pnode p1,p2;
    printf("p1:\n");
    p1=creat();
    printf("d");
    p2=stack(p1);
    bj(p1,p2);
}