let node = llist

while(node != null) {
    if(node.next== null) {
        return llist
    }

    let firstNode = node.data
    let secondNode = node.next.data   

    if(firstNode != secondNode) {
        node = node.next
    }         

    if(firstNode == secondNode) {
        node.next = node.next.next
    }
}

return llist