Vocational rehab demo component

import React, { useState } from "react";
import "./App.css";

function App() {
  const [fibonacci, setFibonacci] = useState(null);
  const [value, setValue] = useState(null);
  const [initialNumber, setInitialNumber] = useState(null);

  function fibonacciHelper(number) {
    if (number < 2) {
      return number;
    }

    return fibonacciHelper(number - 1) + fibonacciHelper(number - 2);
  }

  function submitHandler(event) {
    event.preventDefault();
    setFibonacci(fibonacciHelper(value));
    setValue(null);
  }

  function inputHandler(event) {
    event.preventDefault();
    setValue(event.target.value);
    setInitialNumber(event.target.value);
    setFibonacci(null);
  }
  return (
    <div className="App">
      <form action="" onSubmit={submitHandler}>
        <input type="number" onChange={inputHandler} />
        <button>fibonacci</button>
      </form>
      <h3>
        the fibonacci of {initialNumber} is {fibonacci}
      </h3>
    </div>
  );
}

export default App;