text: const recursiveCircus = input => {
    const programs = input.split('\n').map(p => p.replace(/( \(\d*\))/, '').replace(/ ->/, ',').split(', '))
    const roots = programs.reduce((ret, p) => [p[0], ...ret], [])
    const nodes = programs.reduce((ret, p) => ret.concat(p.slice(1, p.length)), [])
  
    return roots.find(r => !nodes.find(n => n === r))
  }
  
  export default recursiveCircus
  