#include <iostream>
#include <algorithm>
#include <cstdio>
#include <string>

#define ll long long

using namespace std;

int main(){

   int d;
   cin>>d;
   string s="";
   for(int i=0;i<=90;++i) s+=to_string(i);
   cout<<s[d]<<endl;
   return 0;
}