#include<iostream>
#include<algorithm>
#include <vector>
using namespace std;
int main() {
	string A;
	int cnt = 0;
	cin >> A;
	const int Z = A.size();
	if (Z == 1) {
		cout << -1 << endl;
	}
	else {
		if (A.at(0) != '1') {
			cnt++;
		}
		for (int i = 1; i < Z; i++) {
			if (A.at(i) != '3') {
				cnt++;
			}
		}
		if (cnt == 0) {
			cout << Z - 1 << endl;
		}
		if (cnt != 0) {
			cout << -1 << endl;
		}
	}
}