docs: public static int countOccurTimes(String str, String a) {
  		int pos = -2;
  		int n = 0;
  
  		while (pos != -1) {
  			if (pos == -2) {
  				pos = -1;
  			}
  			pos = str.indexOf(a, pos + 1);
  			if (pos != -1) {
  				n++;
  			}
  		}
  		return n;
  	}