#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll=vector<long long>;
template<typename T>
T get(){T r;cin>>r;return r;}

int main() {
    string n=get<string>();
    ll cnt=0;
    if(n[0]=='1'){
        for(int i=1;i!=n.size();i++){
            if(n[i]=='3'){
                cnt++;
            }
            else{
                cnt=-1;
                break;
            }
        }
        cout<<cnt-(cnt==0)<<endl;
    }else{
        cout<<-1<<endl;
    }
    system("pause");
}