B.cpp

#include<bits/stdc++.h>
using namespace std;

int32_t main(){
	#ifndef ONLINE_JUDGE
		freopen("input1.txt", "r", stdin);
		freopen("output1.txt", "w", stdout);
	#endif
 
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
		
		int sum = 0;
    string s; cin >> s;
    for (int i = 0; i < s.size(); i++) sum += s[i] - '0';
    int ans = 1;
    if (s.size() == 1) ans = 0;

    while (sum > 9)
    {
        int temp = sum, newsum = 0;
        while (temp)
        {
            newsum += temp % 10;
            temp /= 10;
        }
        sum = newsum;
        ans++;
    }

    cout << ans << endl;

	return 0;
}