<div id="app"></div>

class HelloWorld extends React.Component {
  render () {
    return (
      <div>
        <h3>Hello</h3>
        <p>Nice to meet you!</p>
      </div>
    )
  }
}

class App extends React.Component {
  render () {
    return (
      <div>
        <HelloWorld />
      </div>
    )
  }
}

ReactDOM.render(
  <App />,
  document.getElementById('app')
)