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

typedef struct node{
    int num;
    struct node *next;
}sq;

sq *head=NULL, *tail;

void create(int n){
    sq *newnode = (sq*) malloc (1*sizeof(sq));
    newnode->data = num;
    newnode->next = NULL;
    if(head==NULL){
        head = newNode;
        tail = newNode;
    }
    else{
        tail = newNode->next;
        tail = newNode;
    }
}
int main(){
    int n,itr;
    scanf("%d",&num);
    if(num<0){
        printf("Invalid input");
    }
    create(num);
    return 0;
}