code: private static String multipleExtractor(String formula) {
          String recentCompoundCount = "0";
          String recentCompound = "";
  
          boolean found = false;
          for (int f = 0; f < formula.length(); f++) {
              char thisChar = formula.charAt(f);
              if (thisChar >= '0' && thisChar <= '9') {
                  if (!found)
                      recentCompoundCount += thisChar;
                  else
                      recentCompound += thisChar;
  
              } else {
                  found = true;
                  recentCompound += thisChar;
              }
          }
          return muliplier(recentCompound, Integer.valueOf(recentCompoundCount));
      }
docs: The starting with numeric value is used to show a quantity by which a formula is multiplied.
  For example: 2H2O really means that a H4O2 unit.
  
  @param formula Formula to correct
  @return        Formula with the correction