#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct node{
    char data[100];
    struct node* next; 
};
struct node* head=NULL;

int createList(){
    struct node* newnode=(struct node*)malloc(sizeof(struct node));
    scanf("%s ", newnode->data);
    newnode->next=NULL;
    int len=strlen(newnode->data);
    for(int i=0;i<len;i++)
    {
        if((newnode->data[i]>='A' && newnode->data[i]<='Z') || (newnode->data[i]>='a' && newnode->data[i]<='z') || (newnode->data[i]>='0' && newnode->data[i]<='9'))
        {
            continue;
        }
        else
        {
            printf("Invalid input");
        }
    }
int main()
{
    struct node* newnode;
    struct node* temp;
    if(head==NULL)
    {
        head=temp=newnode;
    }
    else
    {
        temp=head;
        while(temp->next!=NULL)
        {
            temp=temp->next;
        }
    }
}    
        temp->next=newnode;
    }
}