Java Convert Integer combined with String amount to Integer : I have to use an int value "nid" to work on. But this int value should be an combination of int "did" and String "a"!

    int did = 123456;
    String a = "_b";
    int nid = Integer.parseInt((did+a).toString());

But for this code i get the error message

    java.lang.NumberFormatException: For input string: "123456_b"

Is there any way, to convert a combination of int and string to int?