text: function fiboWithFor(len) {
  	let x = 0, y = 1, tmp = 0;
  	
  	if(len < 2) {
  		return len;
  	}
  	for(let i = 2; i <= len; i++) {
  		tmp = y;
  		y = x + y;
  		x = tmp;
  	}
  	return y;
  }
  
  function fiboWithRec(len) {
  	if(len < 2) {
  		return len;
  	}
  	return fiboWithRec(len-1) + fiboWithRec(len-2);
  }
  