题解 | #游游的整数切割#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        int n = s.length();

        boolean single = true;
        if ((s.charAt(n - 1) - '0') % 2 == 0) {
            single = false;
        }

        int count = 0;
        for (int i = 0; i < n - 1; i++) {
            char c = s.charAt(i);
            if (c == '1' || c == '3' || c == '5' || c == '7' || c == '9') {
                count++;
            }
        }
        System.out.println(single ? count : n - count - 1);
    }
}