Syntax error on token(s), misplaced construct(s) on else if

This is my code. I'm super new to Java. Basically trying to make a super-easy calculator. I get the in the title named error on the else if(add){...etc. Would appreciate any help! Thanks!

import java.io.Console;
import java.util.Scanner;
public class letsgo {

    @SuppressWarnings("resource")
    public static void main(String args[]) {

        Scanner input = new Scanner(System.in);

        System.out.println("Hello, and welcome to my first calculator.");
        System.out.println("Please type your first number here:");
        int num1 = input.nextInt();
        System.out.println("Please type your second number here");
        int num2 = input.nextInt();
        boolean add;
        boolean subtract;


        int answerAdd = num1 + num2;
        int answerSubtract = num1 - num2;
        boolean tryAgain;
        do{
        add = input.hasNext("add");
        subtract = input.hasNext("subtract");
            System.out.println("Do you want to subtract or add?"  );
            if(subtract){
                System.out.println(answerSubtract);}
            else if(add){
                System.out.println(answerAdd);}
            else("AssignmentOperator Expression" (tryAgain)){
                System.out.println("Please say add or subtract instead: ");}
        }
        while(tryAgain);