export function commonChars(a: string, b: string): number {
  // Escribe tu solución aquí

  let newA: Set<string> = new Set(a.toLowerCase());
  let newB: Set<string> = new Set(b.toLowerCase());
  let count: number = 0;

  newA.forEach(letra => {
    if(newB.has(letra)) count++;
  })
  
  return count;
}