#include<iostream>
#include<string>
using namespace std;
int main()
{
    string n;
    cin>>n;
   
    if(n[1]==(0||1||2||3||4||5||6||7||8||9)
    {
        cout<<"Invalid input";
       return 0;
        
    }
 
    }
    cout<<n.length();
 
    
    return 0;
}