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

//const double PI = acos(-1);
using ll = long long;
using ull = unsigned long long;
const int inf = 2e9;
const ll INF = 4e18;
const ll MOD = 1e9+7;


int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);
  string s;
  cin >> s;
  int ans = 0;
  if (s[0] != '1') {
    cout << -1 << endl;
    return 0;
  }
  for (int i = 1; i < s.size(); i++) {
    if (s[i] == '3') ans++;
    else {
      cout << -1 << endl;
      return 0;
    }
  }
  if (s.size() == 1) cout << -1 << endl;
  else cout << ans << endl;
  return 0;
}