public boolean withdraw (int amount) {
    	   if (amount < 0) {
               System.out.println ("Cannot withdraw negative amount.");
               return false;
           } else if (this.myBalance > amount) {
               this.myBalance=this.myBalance-amount;
               return true;
           }else if (this.myBalance < amount && this.parentAccount!=null) {
                 parentAccount.withdraw(amount-this.balance());
          	     this.myBalance=0;
               return true;
           } else{
        	   return false;
           }
    }