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
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.BufferedWriter;
import java.util.InputMismatchException;
import java.util.ArrayList;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author ilyakor
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        OutputWriter out = new OutputWriter(outputStream);
        TaskA solver = new TaskA();
        solver.solve(1, in, out);
        out.close();
    }
}

class TaskA {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
        String s = in.nextToken();
        int[] sum = new int[s.length() + 1];
        sum[0] = 0;
        for (int i = 0; i < s.length(); ++i) {
            sum[i + 1] = sum[i];
            if (s.charAt(i) == '[') ++sum[i + 1];
        }
        int res = 0;
        int rLeft = 0, rRight = 0;
        ArrayList<ii> st = new ArrayList<ii>();
        st.add(new ii(3, -1));
        for (int i = 0; i <= s.length(); ++i) {
            char c = i < s.length() ? s.charAt(i) : 'z';
            if (c == '(' || c == '[') {
                st.add(new ii(c == '(' ? 0 : 1, i));
            } else {
                int cv = c == ')' ? 0 : 1;
                if (c == 'z') cv = 2;
                int sv = st.get(st.size() - 1).first;
                if (cv == sv) {
                    st.remove(st.size() - 1);
                    int cur = sum[i + 1] - sum[st.get(st.size() - 1).second + 1];
                    if (cur > res) {
                        res = cur;
                        rLeft = st.get(st.size() - 1).second + 1;
                        rRight = i + 1;
                    }
                } else {
                    st.clear();
                    st.add(new ii(3, i));
                }
            }
        }
        out.printLine(res);
        if (res > 0) {
            out.printLine(s.substring(rLeft, rRight));
        }
    }
}

class InputReader {
    private InputStream stream;
    private byte[] buffer = new byte[10000];
    private int cur;
    private int count;

    public InputReader(InputStream stream) {
        this.stream = stream;
    }

    public static boolean isSpace(int c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public int read() {
        if (count == -1) {
            throw new InputMismatchException();
        }
        try {
            if (cur >= count) {
                cur = 0;
                count = stream.read(buffer);
                if (count <= 0)
                    return -1;
            }
        } catch (IOException e) {
            throw new InputMismatchException();
        }
        return buffer[cur++];
    }

    public int readSkipSpace() {
        int c;
        do {
            c = read();
        } while (isSpace(c));
        return c;
    }

    public String nextToken() {
        int c = readSkipSpace();
        StringBuilder sb = new StringBuilder();
        while (!isSpace(c)) {
            sb.append((char) c);
            c = read();
        }
        return sb.toString();
    }

    }

class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
        writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
        this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
        for (int i = 0; i < objects.length; i++) {
            if (i != 0) {
                writer.print(' ');
            }
            writer.print(objects[i]);
        }
    }

    public void printLine(Object... objects) {
        print(objects);
        writer.println();
    }

    public void close() {
        writer.close();
    }
}

class ii implements Comparable<ii> {
    public int first;
    public int second;

    public ii() {
    }

    public ii(int first, int second) {
        this.first = first;
        this.second = second;
    }

    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        ii ii = (ii) o;

        if (first != ii.first) return false;
        if (second != ii.second) return false;

        return true;
    }

    public int hashCode() {
        int result = first;
        result = 31 * result + second;
        return result;
    }

    public int compareTo(ii o) {
        if (first != o.first) {
            return first < o.first ? -1 : 1;
        }
        if (second != o.second) {
            return second < o.second ? -1 : 1;
        }
        return 0;
    }

    }

