I have 3 plus and minus buttons on my page. I need all of them to do the same thing once clicked.

html:

  <div class="product1">
        <div class="product1-lable"></div>
        <div class="product1-price"></div>
        <button class="minus">+</button>
        <input class="amount" type="amount" value="0"></input>
        <button class="plus">-</button>
        </div> 

JavaScript:

            let btnAdd = document.querySelector('.plus');
            let btnSubtract = document.querySelector('.minus');
            let input = document.querySelector('input');
            btnAdd.addEventListener('click', () =>{
            input.value = parseInt(input.value) + 1;
            });
            btnSubtract.addEventListener('click', () =>{
            input.value = parseInt(input.value) - 1;
            }); 

Only the first button is working, the other 2 are not.