Евгений

function validBraces(b){
  let reg = /\(\)/g;
  b = b.replace(/[^\(\)]/g,'')
  
  return b.match(reg) != null ? validBraces(b.replace(reg,'')) : b === "" ? true : false;
}

console.log(validBraces("(Sensei saysno) (sd) (sdfsf"));