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

public class Main {
  private static int solve(String s) {
    char[] cs = s.toCharArray();
    int length = cs.length;
    if (length == 1) {
      return 1;
    }
    int[][] dptable = new int[length + 1][3];
    dptable[1][1] = 1;
    dptable[2][2] = 1;
    for (int i = 2; i <= length; i++) {
      for (int j = 1; j <= 2; j++) {
        for (int k = 1; k <= 2; k++) {
          if (j != k && i - k >= 0) {
            dptable[i][j] = Math.max(dptable[i][j], dptable[i - j][k] + 1);
          } else if (j == 1 && i - 2 >= 0 && cs[i-1] != cs[i-2]) {
            dptable[i][j] = Math.max(dptable[i][j], dptable[i - j][k] + 1);
          } else if (j == 2 && i - 4 >= 0 && (cs[i - 2] != cs[i-4] || cs[i-1] != cs[i - 3])) {
            dptable[i][j] = Math.max(dptable[i][j], dptable[i - j][k] + 1);
          }
        }
      }
    }
    /*
    for (int i = 0; i <= length; i++) {
      System.err.printf("%d %d\n", dptable[i][1], dptable[i][2]);
    }
    */
    return Math.max(dptable[length][1], dptable[length][2]);
  }
  
  private static void execute(ContestReader reader, PrintWriter out) {
    String s = reader.next();
    out.println(solve(s));
  }
  
  public static void main(String[] args) {
    ContestReader reader = new ContestReader(System.in);
    PrintWriter out = new PrintWriter(System.out);
    execute(reader, out);
    out.flush();
  }
}

class ContestReader {
  private BufferedReader reader;
  private StringTokenizer tokenizer;
  
  ContestReader(InputStream in) {
    reader = new BufferedReader(new InputStreamReader(in));
  }
  
  public String next() {
    while (tokenizer == null || !tokenizer.hasMoreTokens()) {
      try {
        tokenizer = new java.util.StringTokenizer(reader.readLine());
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
    return tokenizer.nextToken();
  }
  
  public int nextInt() {
    return Integer.parseInt(next());
  }
  
  public long nextLong() {
    return Long.parseLong(next());
  }
  
  public double nextDouble() {
    return Double.parseDouble(next());
  }
  
  public int[] nextIntArray(int n) {
    int[] array = new int[n];
    for (int i = 0; i < n; i++) {
      array[i] = nextInt();
    }
    return array;
  }
  
  public long[] nextLongArray(int n) {
    long[] array = new long[n];
    for (int i = 0; i < n; i++) {
      array[i] = nextLong();
    }
    return array;
  }
}

class Algorithm {
  private static void swap(Object[] list, int a, int b) {
    Object tmp = list[a];
    list[a] = list[b];
    list[b] = tmp;
  }
  
  public static <T extends Comparable<? super T>> boolean nextPermutation(T[] ts) {
    int rightMostAscendingOrderIndex = ts.length - 2;
    while (rightMostAscendingOrderIndex >= 0 &&
        ts[rightMostAscendingOrderIndex].compareTo(ts[rightMostAscendingOrderIndex + 1]) >= 0) {
      rightMostAscendingOrderIndex--;
    }
    if (rightMostAscendingOrderIndex < 0) {
      return false;
    }
    
    int rightMostGreatorIndex = ts.length - 1;
    while (ts[rightMostAscendingOrderIndex].compareTo(ts[rightMostGreatorIndex]) >= 0) {
      rightMostGreatorIndex--;
    }
    
    swap(ts, rightMostAscendingOrderIndex, rightMostGreatorIndex);
    for (int i = 0; i < (ts.length - rightMostAscendingOrderIndex - 1) / 2; i++) {
      swap(ts, rightMostAscendingOrderIndex + 1 + i, ts.length - 1 - i);
    }
    return true;
  }
  
  public static void shuffle(int[] array) {
    Random random = new Random();
    int n = array.length;
    for (int i = 0; i < n; i++) {
      int randomIndex = i + random.nextInt(n - i);
      
      int temp = array[i];
      array[i] = array[randomIndex];
      array[randomIndex] = temp;
    }
  }
  
  public static void shuffle(long[] array) {
    Random random = new Random();
    int n = array.length;
    for (int i = 0; i < n; i++) {
      int randomIndex = i + random.nextInt(n - i);
      
      long temp = array[i];
      array[i] = array[randomIndex];
      array[randomIndex] = temp;
    }
  }
  
  public static void sort(int[] array) {
    shuffle(array);
    Arrays.sort(array);
  }
  
  public static void sort(long[] array) {
    shuffle(array);
    Arrays.sort(array);
  }
}



Measured memory_bytes: 32916