import java.io.*;
import java.util.*;

public class Main {

    public static void main(String[] args) throws IOException {
        FastScanner in = new FastScanner(/*new InputStreamReader(new FileInputStream(new File("dijkstra.in")))); */ System.in);
        FastPrinter out = new FastPrinter(/*new OutputStreamWriter(new FileOutputStream(new File("dijkstra.out")))); */  System.out);
        String s = in.next();
        if(s.length() == 1) System.out.println(0);
        else {
            int max = 0;
            for (int i = 0; i < s.length()-1; i++) {
                if (s.charAt(i) != s.charAt(i + 1)) {
                    max = Math.max(1, max);
                    i++;
                }
                else {
                    int l = i;
                    int k = 1;
                    int maxk = 0;
                    while (k > 0){
                        maxk = Math.max(k, maxk);
                        i++;
                        if(i == s.length()) break;
                        if(s.charAt(l) == s.charAt(i)){
                            k++;
                        }
                        else k--;
                    }
                    max = Math.max(max, maxk-k);
                }
            }
            System.out.println(max);
        }
        out.close();
    }
}


class FastPrinter {
    private final PrintWriter writer;

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

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

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

    public void println(long i) {
        writer.println(i);
    }

    public void println(double d) {
        writer.println(d);
    }

    public void println(String s) {
        writer.println(s);
    }

    public void println(String format, Object... args) {
        println(String.format(format, args));
    }

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

    public void print(long i) {
        writer.print(i);
    }

    public void print(char c) {
        writer.print(c);
    }

    public void print(double d) {
        writer.print(d);
    }

    public void print(String s) {
        writer.print(s);
    }

    public void print(String format, Object... args) {
        print(String.format(format, args));
    }

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

class FastScanner {

    private BufferedReader reader;
    private StringTokenizer st;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private SpaceCharFilter filter;

    public FastScanner(InputStream stream) {
        this.reader = new BufferedReader(new InputStreamReader(stream));
        this.st = new StringTokenizer("");
    }

    public FastScanner(InputStreamReader stream) {
        this.reader = new BufferedReader(stream);
        this.st = new StringTokenizer("");
    }

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

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

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

    public String next() {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(readLine());
        }
        return st.nextToken();
    }

    public String nextLine() {
        st = new StringTokenizer("");
        return readLine();
    }

    public String tryNextLine() {
        st = new StringTokenizer("");
        return tryReadLine();
    }

    private String readLine() {
        String line = tryReadLine();
        if (line == null) throw new InputMismatchException();
        return line;
    }

    private String tryReadLine() {
        try {
            return reader.readLine();
        } catch (IOException e) {
            throw new InputMismatchException();
        }
    }

    public int[] nextIntArray(int size) {
        int[] array = new int[size];
        for (int i = 0; i < size; i++)
            array[i] = nextInt();
        return array;
    }

    public int[][] nextIntTable(int rowCount, int columnCount) {
        int[][] table = new int[rowCount][];
        for (int i = 0; i < rowCount; i++)
            table[i] = nextIntArray(columnCount);
        return table;
    }

    public long[] nextLongArray(int size) {
        long[] array = new long[size];
        for (int i = 0; i < size; i++)
            array[i] = nextLong();
        return array;
    }

    public long[][] nextLongTable(int rowCount, int columnCount) {
        long[][] table = new long[rowCount][];
        for (int i = 0; i < rowCount; i++)
            table[i] = nextLongArray(columnCount);
        return table;
    }

    public boolean isSpaceChar(int c) {
        if (filter != null)
            return filter.isSpaceChar(c);
        return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
        return c == ' ' || c == '\t' || isEOL(c);
    }

    public static boolean isEOL(int c) {
        return c == '\n' || c == '\r' || c == -1;
    }

    public interface SpaceCharFilter {
        public boolean isSpaceChar(int ch);
    }
}