import java.util.ArrayList;
import java.io.IOException;

public class Infix {
    private ArrayList<Character> chars;
    private int index;
    
    public static void main(String[] args) {
        String str = "+++12-835";
        if (args.length > 0) {
            str = args[0];
        }
        try {
            Infix parser = new Infix(str);
        } catch (Exception e) {
            System.out.println("error");
        }
    }
    
    public Infix(String terminals) throws IOException {
        this.index = 0;
        this.chars = new ArrayList<Character>();
        for (char c: terminals.toCharArray()) 
            this.chars.add(c);
        
        this.list();

        if (this.index < this.chars.size())
            throw new IOException("Could not parse entire string");
        
        System.out.println();
    }

    private void list() throws IOException {
        char lookahead = this.lookahead();
        if (lookahead == '+' || lookahead == '-') {
            match(lookahead);
            System.out.write('(');
            list();
            System.out.write(lookahead);
            list();
            System.out.write(')');
        }
        else if (lookahead >= '0' && lookahead <= '9') 
            digit();
        else 
            throw new IOException("Expected lookahead to be a digit or plus/minus");
    }

    private void digit() throws IOException {
        char lookahead = this.lookahead();
        if (lookahead >= '0' && lookahead <= '9') {
            match(lookahead);
            System.out.write(lookahead);
            return;
        }
        throw new IOException("Expected lookahead to be a digit");
    }

    private void match(char t) throws IOException {
        boolean matches = this.lookahead() == t;

        if (matches) 
            this.index += 1;
        else if (!matches) 
            throw new IOException("Expected " + (char)this.lookahead() + " to match " + (char)t);
    }

    private char lookahead() {
        return this.chars.get(this.index);
    }
}