NutrientTree

import java.util.*;
import java.io.*;
public class NutrientTree {

    static Node createTree(String s) {
        s = s.trim();
        if(s.charAt(0) != '(') {
            return new Node(Integer.parseInt(s));
        }else {
            s = s.substring(1, s.length() - 1).trim();

            int ind = -1;

            if(s.charAt(0) != '(') {
                ind = s.indexOf(' ');
            }else {
                int count = 0;
                for(int i = 0; i < s.length(); i ++) {
                    if(s.charAt(i) == '(') {
                        count ++;
                    }else if(s.charAt(i) == ')') {
                        count --;
                    }
                    if(count == 0) {
                        ind = i;
                        break;
                    }
                }
            }
            return new Node(createTree(s.substring(0, ind + 1)), createTree(s.substring(ind + 1)));
        }
    }

    static void solve(Node tree, int x) {
        if(tree.lc == null) {
            tree.dp = new int[x + 1];
            for(int i = 0; i <= x; i ++) {
                tree.dp[i] = tree.v + i;
            }
        }else {
            solve(tree.lc, x);
            solve(tree.rc, x);

            int[] dpl = new int[x + 1];
            for(int i = 0; i <= x; i ++) {
                int max = 0;

                for(int j = 0; j <= i; j ++) {
                    max = Math.max(Math.min((1 + j) * (1 + j), tree.lc.dp[i - j]), max);
                }
                dpl[i] = max;
            }

            int[] dpr = new int[x + 1];
            for(int i = 0; i <= x; i ++) {
                int max = 0;

                for(int j = 0; j <= i; j ++) {
                    max = Math.max(Math.min((1 + j) * (1 + j), tree.rc.dp[i - j]), max);
                }
                dpr[i] = max;
            }

            tree.dp = new int[x + 1];

            for(int i = 0; i <= x; i ++) {
                int max = 0;
                for(int j = 0; j <= i; j ++) {
                    max = Math.max(dpl[j] + dpr[i - j], max);
                }
                tree.dp[i] = max;
            }
        }
    }

    public static void main(String[] args) throws IOException{
        String s = in.readLine();
        readLine();
        int x = nextInt();

        Node root = createTree(s);

        solve(root, x);

        System.out.println(root.dp[x]);

    }
    static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    static StringTokenizer st;
    static void readLine() throws IOException{
        st = new StringTokenizer(in.readLine());
    }
    static int nextInt() {
        return Integer.parseInt(st.nextToken());
    }



    static class Node{
        int[] dp;
        int v;
        Node lc, rc;
        Node(int v){
            this.v = v;
            lc = null;
            rc = null;
        }
        Node(Node lc, Node rc){
            v = 0;
            this.lc = lc;
            this.rc = rc;
        }
        void print() {
            if(lc == null) {
                System.out.println(v);
            }else {
                System.out.println("this is node");
                lc.print();
                rc.print();
            }
        }
    }

}