/* We can't call insert last or insert any function when our linked list is empty. So if there is no data in our linked list and we want to use insert last or insert any function then we called insert first function there. Again if we have one data in our linked list and we want to use delete the last function, then we called delete the first function */
/* Here we create two stack. First we push some data in our first stack. Then if we pop any data from our first stack that will be pushed in our second stack. So we will not lose any data. There are two different display function for two different stack. */