#include<bits/stdc++.h>
using namespace std;
int main()
{
    int a;
    cin>>a;
    if(a<10) cout<<"1";
    else if(a<100) cout<<"2";
    else if(a<1000) cout<<"3";
    else cout<<"4";
    return 0;
}
/**************************************************************
	Problem: 1710
	User: linmiaoling
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/