Function to determine how many bars I need for different pieces of different sizes

Question

I'm trying to create a function that calculates how many 6-meter bars I need for different pieces of different sizes. For example, if I need 3 pieces, each 4 meters long, I obviously need 3 bars, but I can't seem to create a function that does that. Please help.

I tried to create a list and have another function count the leftovers of the iteration based on the input value, but I didn't succeed.

   let trozos = [];
        /*add number of pieces*/
        function agregarTrozos() {
            const numTrozos = parseInt(document.getElementById("trozos").value);
            const tamanoTrozo = parseFloat(document.getElementById("tamano").value);
            
            if (!isNaN(numTrozos) && !isNaN(tamanoTrozo)) {
                for (let i = 0; i < numTrozos; i++) {
                    trozos.push(tamanoTrozo);
                    actualizarListaTrozos();
                }
                document.getElementById("trozos").value = "";
                document.getElementById("tamano").value = "";
            }
        }
        /*update number of chunks*/
        function actualizarListaTrozos() {
            const listaTrozos = document.getElementById("listaTrozos");
            listaTrozos.innerHTML = "";
            trozos.forEach(tamano => {
                const li = document.createElement("li");
                li.textContent = tamano + " meters";
                listaTrozos.appendChild(li);
            });
        }
        /*calculation of necessary bars*/
        function calcularBarras() {
            const longitudBarra = 6;
            let longitudTotal = trozos.reduce((total, tamano) => total + tamano, 0);
            let barrasNecesarias = 0;
            
            while (longitudTotal > 0) {
                barrasNecesarias++;
                longitudTotal -= longitudBarra;
            }
            
            document.getElementById("resultado").textContent = barrasNecesarias;
        }
            /* clean */
        function limpiar() {
            trozos = [];
            actualizarListaTrozos();
            document.getElementById("resultado").textContent = "";
        }
  

<div id="container">
    <h1>Bar Calculator</h1>
    <p>Each bar measures 6</p>
    <label for="trozos">Number of Pieces:</label>
    <input type="number" id="trozos">
    <label for="tamano">Piece Size (meters):</label>
    <input type="number" id="tamano">
    <button onclick="agregarTrozos()">Add</button>
    <hr>
    <h2>Metal Pieces</h2>
    <ul id="listaTrozos"></ul>
    <hr>
    <button onclick="calcularBarras()">Calculate Necessary Bars</button>
    <h2>Necessary Bars: <span id="resultado"></span></h2>
    <button onclick="limpiar()">Clean</button>