#include<bits/stdc++.h>
using namespace std;
int main(){ 
    int n;
    cin>>n;
    if(n<=10&&n>=100)cout<<2;
    if(n<=100&&n>=1000)cout<<3;
    if(n<=1000&&n>=10000)cout<<4;
    
}
/**************************************************************
	Problem: 1710
	User: yangjunwen
	Language: C++
	Result: Wrong Answer
****************************************************************/