#include <iostream>
#include <list>
#include <vector>
#include <string>
#include <stdio.h>
#include <stdint.h>
#include <iomanip>
using namespace std;

using uint = unsigned int;
using ll = long long;

#define CIN( LL , A ) LL A; cin >> A 
#define GETLINE( A ) string A; getline( cin , A ) 
#define FOR_ITR( ARRAY , ITR , END ) for( auto ITR = ARRAY .begin() , END = ARRAY .end() ; ITR != END ; ITR ++ ) 

int main()
{

  CIN( ll , D );

  if( D <= 9 ){

    cout << D << endl;

  } else {

    D -= 10;

    if( D % 2 == 0 ){
      
      cout << ( D / 20 ) + 1 << endl;

    } else {

      cout << ( ( D - 1 ) / 2 ) % 10 << endl;

    }

  }
  
  return 0;

}