#include <iostream>
using namespace std;

int main(void){
    char c;
    int i=0;
    
    cin >> c;
    if(c != '1'){
        cout << -1 << endl;
        return 0;
    }
    
    while(cin >> c){
        if(c != '3'){
            i = -1;
            break;
        }
        i++;
    }
    if(i == 0){
        i = -1;
    }
    cout << i << endl;
    return 0;
}