import java.util.*;

public class resumo {
    public static void main( String[] args ){
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        scanner.close();
        System.out.println(get_ans(n));
    }


    public static List<Integer> get_digits( int n ){
        List<Integer> digits = new ArrayList<>();
        for( ; n > 0; n /= 10 ) digits.add(n%10); 
        return digits; 
    }

    public static int get_num( List<Integer> digits ){
        int num = 0; 
        for( int x : digits ) num = 10*num + x; 
        return num;
    }

    public static int resumir( int n ){
        List<Integer> digits = get_digits(n);
        int total = 0, impares = 0, pares = 0; 
        for( int x : digits ){
            total++; 
            if( x%2 == 1 ) impares++; 
            else pares++;
        }
        return 100*total + 10*impares + pares; 
    }

    public static int get_ans( int n ){
        int ans = 0;
        for(; n != resumir(n); n = resumir(n) ) ans++;
        return ans;
    }
}