#include <iostream>

using namespace std;

int main(int argc, char ** argv){
  int N;
  cin >> N;
  
  int digit = 0;
  while(true){
    if(N % 10 == 1){
       if(N > 10){
         digit = -1;
       }
       break;
    }
    else if(N % 10 == 3){
       if(N < 10){
          digit = -1;
          break;
       }
       digit++;
    N = N / 10;
    }
    else{
        digit = -1;
        break;
    }
  }
  
  cout << digit;
}