import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
 
 
public class Main {
	
	public static void main(String[] args) throws IOException {
		Main m = new Main();
		//*
		m.input();
		m.solve();
		m.output();
		/*/
		m.debug();
		//*/
	}
	
	public void debug() {
	}
	
	//*
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	/*/
	InputUtil in = new InputUtil();
	//*/
	PrintWriter out = new PrintWriter(System.out);
	char[] S = null;
	int ans = 0;

	public void input() throws IOException {
		//*
		S = br.readLine().toCharArray();
		/*/
		X = in.nextInt();
		Y = in.nextInt(new int[N]);
		//*/
	}
	
	public void solve() throws IOException {
		ArrayList<Integer> s2 = makeKukanNagasaList();
		int totalLength = S.length;
		if(s2.size() == 1){
			ans = s2.get(0);
		}else if (s2.size() ==2){
			ans = Math.max(s2.get(0), s2.get(1));
		}else {
			int sum1 = 0;
			int K = totalLength;
			for(int i=0; i<s2.size(); i++){
				sum1 += s2.get(i);
				K = Math.min(K, Math.max(sum1, totalLength-sum1));
			}
			ans = K;
		}
		
	}
	
	private ArrayList<Integer> makeKukanNagasaList() {
		ArrayList<Integer> s2 = new ArrayList<>();
		int count = 0;
		ans = -1;
		char pre = '2';
		for(char s : S) {
			if(pre != s) {
				if (count > 0){
					s2.add(count);
				}
				count = 1;
			}else{
				count ++;
			}
			pre = s;
		}
		s2.add(count);
		return s2;
	}
	
	
	public void output() {
		out.println(ans);
		out.flush();
	}
}

//*
class InputUtil {
	//Static Fields
	private static final int BUFSIZ = 100000;
	
	//Fields
	protected InputStream in;
	private byte[] buf = null;
	private int ptr = 0;
	private int max = -1;
	private DataInputStream dis = null;
	//Constructors
	public InputUtil() {this(System.in,BUFSIZ);}
	public InputUtil(InputStream in, int bufsiz) {
		initBuf(bufsiz);
		initIn(in);
	}
	
	//Methods
	//Initializer
	protected void initIn(InputStream in) {dis = new DataInputStream(this.in = in);}
	protected void initBuf(int bufsiz) {buf = new byte[bufsiz];}
	
	//buffer operation
	private void next() throws IOException {ptr++; readBuf();}
	private void readBuf() throws IOException {
		if(ptr >= max && dis.available()>0) {
			if(max>0) Arrays.fill(buf,0,max,(byte)0);
			max = dis.read(buf);
			ptr = 0;
		}
	}
	
	//Number Input Reader/Parser
	private boolean isNum(byte b) {return '0' <= b && b <= '9'; }
	private boolean isMinus(byte b) {return b=='-'; }
 
	private int _nextInt() throws IOException {
		int sign = 1;
		int res = 0;
		byte c;
		while (!isNum(c=buf[ptr]) && !isMinus(c)) 
			next();
		if (isMinus(buf[ptr])) {
			sign = -1;
			next();
		}
		while (isNum(c=buf[ptr])) {
			res *= 10;
			res += c - '0' ;
			next();
		}
		next();
		return sign * res;
	}
	
	public int nextInt() throws IOException {
		readBuf();
		return _nextInt();
	}
 
	public int[] nextInt(int[] result) throws IOException {
		readBuf();
		for(int i=0; i<result.length; i++) {
			result[i] = _nextInt();
		}
		return result;
	}
	
	//Close 
	public void close() throws IOException {
		if(!this.in.equals(System.in)) 
			this.in.close();
	}
}
//*/

Measured memory_bytes: 25172