#include <stdio.h>
#include <stdlib.h>

struct node
{
    int data;
    struct node *next;
};

display(struct node *head)
{
    if(head == NULL)
    {
        printf("NULL\n");
    }
    else
    {
        printf("%d\n", head -> data);
        display(head->next);
    }
}

void concatenate(struct node *a,struct node *b)
{
    if( a != NULL && b!= NULL )
    {
        if (a->next == NULL)
            a->next = b;
        else
            concatenate(a->next,b);
    }
    else
    {
        printf("Either a or b is NULL\n");
    }
}

int main()
{
    struct node *prev,*a, *b, *p;
    int n,i;
    printf ("number of elements in a:");
    scanf("%d",&n);
    a=NULL;
    for(i=0;i<n;i++)
    {
        p=malloc(sizeof(struct node));
        scanf("%d",&p->data);
        p->next=NULL;
        if(a==NULL)
            a=p;
        else
            prev->next=p;
        prev=p;
    }
    printf ("number of elements in b:");
    scanf("%d",&n);
    b=NULL;
    for(i=0;i<n;i++)
    {
        p=malloc(sizeof(struct node));
        scanf("%d",&p->data);
        p->next=NULL;
        if(b==NULL)
            b=p;
        else
            prev->next=p;
        prev=p;
    }
    concatenate(a,b);
    return 0;
}