#include <bits/stdc++.h>

using namespace std;

int main(){
  string S;
  cin >> S;
  int v[10] = {};
  for(auto& p : S) v[p - '0']++;
  if(v[1]==1&&v[3]>0&&v[1]+v[3]==S.size())cout<<v[3]<<endl;
  else cout << -1 << endl;
}