#include <bits/stdc++.h>
#define int long long 
using namespace std;


signed main() {
string S;
cin >> S;

bool fg = true;
if( S.size() == 1 ) fg = false;
for( int i = 0; i < S.size(); i++ ){
if( i == 0 && S.at(i) != '1' ) fg = false;
if( i > 0 && S.at(i) != '3' ) fg = false;
}

if( fg ) cout << (int)S.size() - 1 << endl;
else cout << -1 << endl;
}