import java.io.*;
import java.util.*;
import java.awt.geom.*;

/**
 * Solution to Persistence
 * 
 * @author vanb
 */
public class persistence_vanb
{
    public Scanner sc;
    public PrintStream ps;
        
    /**
     * Driver.
     * @throws Exception
     */
    public void doit() throws Exception
    {
        sc = new Scanner( System.in );
        ps = System.out;
        
        long number = sc.nextLong();
        int count = 0;
        
        // While the number has more than 1 digit...
        while( number >= 10 )
        {
            int newnumber = 1;
            
            // While this number still has digits to multiply...
            while( number>0 )
            {
                // Get the last digit
                newnumber *= number%10;
                
                // Scoot the number over 1 digit
                number /= 10;
            }
            
            number = newnumber;
            ++count;
        }
        
        ps.println( count );   
    }
    
    /**
     * @param args
     */
    public static void main( String[] args ) throws Exception
    {
        new persistence_vanb().doit();        
    }   
}