function task6() {
  function checkSpam(str) {
    str = str.toLowerCase();
    return !!(~str.indexOf('spam') || ~str.indexOf('sex'));
  }

  console.log(checkSpam('get new Sex videos')); //true
  console.log(checkSpam('[SPAM] How to earn fast money?')); //true
  console.log(checkSpam('New PSD template')); //false
}