#include<iostream>
#include<cstdio>
#include<cstring>
#include<map>
#include<cmath>
#include<queue>
#include<algorithm>
#include<vector>
using namespace std;
int s[10],cnt=0,n,xiao[10],he,he2;
int cmp (int a,int b)
{

	return a>b;
}
int main()
{
   ios::sync_with_stdio(0);
   cin>>n;
   while(n!=495)
   {
   	s[1]=n/100;
     s[2]=n%100/10;
     s[3]=n%10;
	 sort(s+1,s+4,cmp);
	 s[1]=n/100;
     s[2]=n%100/10;
     s[3]=n%10;
	 xiao[1]=s[3];
	 xiao[2]=s[2];
	 xiao[3]=s[1];
	 n=(s[1]*100+s[2]*10+s[3])-(xiao[1]*100+xiao[2]*10+xiao[3]); 
	 cnt++;
   } 
   cout<<cnt-1<<endl;
}