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

ll N, M, K;

int main()
{
    string s;
    cin >> s;
    for (int i = 1; i < s.size(); i++)
    {
        if (s[0] == '1' && s[i] != '3')
        {
            puts("-1");
            return 0;
        }
    }
    cout << s.size() - 1 << endl;
}