My HTML code is not working

on clicking the ADD button it does not append the given string in the unordered list tag

```
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        *{
            font-family: "Arial",cursive;
        }
    </style>

</head>
<body>
<label>
    <input id="todo">
</label>

<button id="btn">ADD</button>
<ul id=list">
    <li>Task 1</li>
</ul>
<script>
    let Todo_box=document.getElementById("todo")
    let todo_list=document.getElementById("list")
    let button=document.getElementById("btn")
    button.onclick=function() {
        let task = Todo_box.value
        let new_element = document.createElement("li")
        new_element.innerText=task;
        todo_list.appendChild(new_element)
    }
</script>
</body>
</html>
```