Kevin has just recevied his disappointing results on the USA Identification of Cows Olympiad (USAICO) in the form of a binary string of length n. Each character of Kevin's string represents Kevin's score on one of the n questions of the olympiad—'1' for a correctly identified cow and '0' otherwise.

However, all is not lost. Kevin is a big proponent of alternative thinking and believes that his score, instead of being the sum of his points, should be the length of the longest alternating subsequence of his string. Here, we define an alternating subsequence of a string as a not-necessarily contiguous subsequence where no two consecutive elements are equal. For example, {0, 1, 0, 1}, {1, 0, 1}, and {1, 0, 1, 0} are alternating sequences, while {1, 0, 0} and {0, 1, 0, 1, 1} are not.

Kevin, being the sneaky little puffball that he is, is willing to hack into the USAICO databases to improve his score. In order to be subtle, he decides that he will flip exactly one substring—that is, take a contiguous non-empty substring of his score and change all '0's in that substring to '1's and vice versa. After such an operation, Kevin wants to know the length of the longest possible alternating subsequence that his string could have.

Input

The first line contains the number of questions on the olympiad n (1 ≤ n ≤ 100 000).

The following line contains a binary string of length n representing Kevin's results on the USAICO. 

Output

Output a single integer, the length of the longest possible alternating subsequence that Kevin can create in his string after flipping a single substring.

Examples

Input

8
10000011


Output

5


Input

2
01


Output

2

Note

In the first sample, Kevin can flip the bolded substring '10000011' and turn his string into '10011011', which has an alternating subsequence of length 5: '10011011'.

In the second sample, Kevin can flip the entire string and still have the same score.


import java.io.*;
import java.math.BigInteger;
import java.util.StringTokenizer;

/**
 * Created by Leonti on 2015-12-04.
 */


public class C {
    public static void main(String[] args) {
        InputReader inputReader = new InputReader(System.in);
        PrintWriter printWriter = new PrintWriter(System.out, true);

        int n = inputReader.nextInt();
        String binS = inputReader.next();
        int res = 1;

        for (int i = 1; i < n; i++) {
            if (binS.charAt(i) != binS.charAt(i - 1)) res++;
        }

        printWriter.print(Math.min(n, res + 2));
        printWriter.close();
    }

    private static class InputReader {
        private final BufferedReader reader;
        private StringTokenizer tokenizer;

        public InputReader(InputStream in) {
            reader = new BufferedReader(new InputStreamReader(in));
        }

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

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

        public double[] nextDoubleArray(int size) {
            double[] array = new double[size];
            for (int i = 0; i < size; ++i) {
                array[i] = nextDouble();
            }
            return array;
        }

        public String[] nextStringArray(int size) {
            String[] array = new String[size];
            for (int i = 0; i < size; ++i) {
                array[i] = next();
            }
            return array;
        }

        public boolean[][] nextBooleanTable(int rows, int columns, char trueCharacter) {
            boolean[][] table = new boolean[rows][columns];
            for (int i = 0; i < rows; ++i) {
                String row = next();
                assert row.length() == columns;
                for (int j = 0; j < columns; ++j) {
                    table[i][j] = (row.charAt(j) == trueCharacter);
                }
            }
            return table;
        }

        public char[][] nextCharTable(int rows, int columns) {
            char[][] table = new char[rows][];
            for (int i = 0; i < rows; ++i) {
                table[i] = next().toCharArray();
                assert table[i].length == columns;
            }
            return table;
        }

        public int[][] nextIntTable(int rows, int columns) {
            int[][] table = new int[rows][columns];
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < columns; j++) {
                    table[i][j] = nextInt();
                }
            }
            return table;
        }

        public long[][] nextLongTable(int rows, int columns) {
            long[][] table = new long[rows][columns];
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < columns; j++) {
                    table[i][j] = nextLong();
                }
            }
            return table;
        }

        public double[][] nextDoubleTable(int rows, int columns) {
            double[][] table = new double[rows][columns];
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < columns; j++) {
                    table[i][j] = nextDouble();
                }
            }
            return table;
        }

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

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

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

        public BigInteger nextBigInteger() {
            return new BigInteger(next());
        }

        public boolean hasNext() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                String line = readLine();
                if (line == null) {
                    return false;
                }
                tokenizer = new StringTokenizer(line);
            }
            return true;
        }

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

        public String readLine() {
            String line;
            try {
                line = reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            return line;
        }
    }
}