#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> P;
 
const int INF = 1e9;
const int mod = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);

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

    return 0;
}