A bracket sequence is a string, containing only characters "(", ")", "[" and "]".

A correct bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters "1" and "+" between the original characters of the sequence. For example, bracket sequences "()[]", "([])" are correct (the resulting expressions are: "(1)+[1]", "([1+1]+1)"), and "](" and "[" are not. The empty string is a correct bracket sequence by definition.

A substring s[l... r] (1 ≤ l ≤ r ≤ |s|) of string s = s1s2... s|s| (where |s| is the length of string s) is the string slsl + 1... sr. The empty string is a substring of any string by definition.

You are given a bracket sequence, not necessarily correct. Find its substring which is a correct bracket sequence and contains as many opening square brackets «[» as possible.

Input

The first and the only line contains the bracket sequence as a string, consisting only of characters "(", ")", "[" and "]". It is guaranteed that the string is non-empty and its length doesn't exceed 105 characters.

Output

In the first line print a single integer — the number of brackets «[» in the required bracket sequence. In the second line print the optimal sequence. If there are more than one optimal solutions print any of them.

Examples

Input

([])


Output

1
([])


Input

(((


Output

0

// @author Sanzhar
import java.io.*;
import java.util.*;
import java.awt.Point;

public class Template {

    BufferedReader in;
    PrintWriter out;
    StringTokenizer st;

    String next() {
        while (st == null || !st.hasMoreTokens()) {
            try {
                st = new StringTokenizer(in.readLine());
            } catch (Exception e) {
            }
        }
        return st.nextToken();
    }

    int nextInt() {
        return Integer.parseInt(next());
    }

    long nextLong() {
        return Long.parseLong(next());
    }

    double nextDouble() {
        return Double.parseDouble(next());
    }

    public void run() throws Exception {
        //in = new BufferedReader(new FileReader("input.txt"));
        //out = new PrintWriter(new FileWriter("output.txt"));
        in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);
        solve();
        out.flush();
        out.close();
        in.close();
    }

    public void solve() throws Exception {
        char[] c = next().toCharArray();
        int n = c.length;
        int x = 0, y = 0, z = 0;
        ArrayDeque<Character> q = new ArrayDeque<Character>();
        int[] ll = new int[n];
        int[] rr = new int[n];
        int[] kk = new int[n];
        int t = 0;
        int l = 0, r = 0, k = 0;
        boolean ok = false;
        for (int i = 0; i < n; i++) {
            if (c[i] == '(' || c[i] == '[') {
                q.addFirst(c[i]);
                if (ok) {
                    ll[t] = l;
                    rr[t] = r;
                    kk[t] = k;
                    t++;
                    ok = false;
                }
            } else if (!q.isEmpty()) {
                char cc = q.remove();
                if ((cc == '(' && c[i] == ')') || (cc == '[' && c[i] == ']')) {
                    if (ok) {
                        l--;
                        r++;
                    } else {
                        l = i - 1;
                        r = i + 1;
                        k = 0;
                        ok = true;
                    }
                    if (t > 0 && l == rr[t - 1]) {
                        l = ll[t - 1];
                        k += kk[t - 1];
                        t--;
                    }
                    if (cc == '[') {
                        k++;
                    }
                    if (k >= z) {
                        x = l;
                        y = r;
                        z = k;
                    }
                } else {
                    ok = false;
                    k = 0;
                    q.clear();
                }
            }
        }
        out.println(z);
        for (int i = x; i < y; i++) {
            out.print(c[i]);
        }
        out.println();
    }

    public static void main(String[] args) throws Exception {
        new Template().run();
    }
}
