#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  ll n;
  cin >> n;
  function<ll(ll)> f = [&](ll x) {
    if (x < 10) return 0LL;
    string s = to_string(x);
    ll t = 1;
    for (char c : s) t *= c - '0';
    return f(t) + 1;
  };
  cout << f(n) << endl;
  return 0;
}