package javaapplication1;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Scanner;


class Tree {
    Tree left;
    Tree right;
    int valRoot;
    int valL;
    int valR;
    int sum;
    int index;
    boolean empty = false;
    boolean leaf = false;
    public Tree(Scanner sc, int parentSum){
        sc.useDelimiter("\\s+");
        sc.next();
        if (sc.hasNextInt()){
            valRoot = sc.nextInt();
            sum = parentSum + valRoot;
        }
        else
            empty = true;
        if(!empty){
            left = new Tree(sc, sum);
            right = new Tree(sc, sum);
            if(left.empty && right.empty)
                leaf = true;
            checkBranch();
        }
        else {
            valR = 0;
            valL = 0;
        }
        String g = sc.next(); //)
    }

    public void checkBranch(){
        if(leaf == true){
            if (JavaApplication1.inSum == sum)
                JavaApplication1.isOK = true;
        }
    }
}

public class JavaApplication1 {

    /**
     * @param args the command line arguments
     */
    static int inSum;
    static boolean isOK;
    public static void main(String[] args) throws FileNotFoundException {

        Scanner sc = null;
        String p;
        StringBuilder line = new StringBuilder();
        try {
            sc = new Scanner(new BufferedReader(new FileReader("test")));
            sc.useDelimiter("\\s+");
            inSum = sc.nextInt();

            while(sc.hasNext()){
                line.append(sc.next());
            }
            p = new String(line.toString());
            p = p.replaceAll("\\(", " ( ");
            p = p.replaceAll("\\)", " ) ");
        } finally {
            if(sc != null)
                sc.close();
        }
        sc = new Scanner(p);
        sc.useDelimiter("\\s+");
        while (sc.hasNext("\\(")){
            Tree t = new Tree(sc, 0);
            if (isOK)
                System.out.println("yes");
            else
                System.out.println("no");
            isOK = false;
            if(sc.hasNextInt())
                inSum = sc.nextInt();
        }
    }
}