#include <iostream>
#include <vector>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <string>
#include <queue>
#include <numeric>
#include "bits/stdc++.h"
using namespace std;

#define INF 100000000

int main() {
   string N;
   cin >> N;
   bool flag = N[0] == '1' ? true : false;
   int counter = 0;
   for (int i = 1; i < N.size(); i++) {
       if (N[i] == '3') {
           counter += 1;
       } else {
           flag = false;
       }
   }
   if (!flag) {
       cout << -1 << endl;
   } else {
       cout << counter << endl;
   }
}