#include<bits/stdc++.h>
using namespace std;
int min_int(int a)
{
    int c[3];
    c[0]=a/100%10;
    c[1]=a/10%10;
    c[2]=a%10;
    sort(c,c+3);
    return c[0]*100+c[1]*10+c[2];
}
int max_int(int a)
{
    int c[3];
    c[0]=a/100%10;
    c[1]=a/10%10;
    c[2]=a%10;
    sort(c,c+3);
    return c[2]*100+c[1]*10+c[0];
}
int main()
{
    int a=0;
    int b;
    cin>>b;
    while(1)
    {
        if(b==495)break;
        b=max_int(b)-min_int(b);
        a++;
    }
    cout<<a;
}