import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int length = s.length();
        int ans;
        if (length % 2 == 0) {
            ans = length / 2;
        } else {
            ans = length / 2 + 1;
        }
        System.out.println(ans);
    }
}