class Solution {
	
	private static boolean f=false;
	public static ListNode addTwoNumbers(ListNode l1, ListNode l2) {
		Stack<Integer> stack=new Stack<>();
		
		while(l1!=null && l2!=null) {
			int v= l1.val+l2.val;
			stack.push((f?(v+1):v)%10);
			if(v>9)
				f=true;
			else
				f=false;
			l1=l1.next;
			l2=l2.next;
		}
		if(f)
			stack.push(1);
		ListNode node =new ListNode(0);
		while(!stack.isEmpty()) {
			ListNode temp = new ListNode(stack.pop());
			temp.next=node.next;
			node.next=temp;
		}
		node=node.next;
        return node;
    }
}