解码

import java.util.Scanner;

public class Main {
    public static int process(char[] ch, int i) {
        if (i == ch.length) {
            return 1;
        }
        if (ch[i] == '0') {
            return 0;
        }
        if (ch[i] == '1') {
            int res = process(ch, i + 1);
            if (i + 1 < ch.length) {
                res += process(ch, i + 2);
            }
            return res;
        }
        if (ch[i] == '2') {
            int res = process(ch, i + 1);
            if (i + 1 < ch.length && ch[i] >= '0' && ch[i + 1] <= '6') {
                res += process(ch, i + 2);
            }
            return res;
        }
        return process(ch, i + 1);
    }


    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        if (str.length() < 1) {
            System.out.println(0);
        } else {
            System.out.println(process(str.toCharArray(), 0));
        }
    }
}