#include<bits/stdc++.h>
using namespace std;
int main(){ 
    int n;
    cin>>n;
    if(n<10) cout<<1;
    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: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/