class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        struct ListNode *new_list;
        while(head->next != NULL)
        {
            struct ListNode *new_node = head->next;
            while(new_node->next != NULL)
            {
                if(head->val == new_node->val)
                {
                    head->next = new_node->next;
                    break;
                }
                new_node = new_node->next;
            }
            if(new_node->next == NULL)
            {
                new_list = head;
                new_list->next = new_node;
            }
            head = head->next;
        }
        return new_list;
    }
};