#include <bits/stdc++.h>
using namespace std;

unsigned champernowne(const unsigned &n) {
  if (n < 10) return n;
  if (n % 2 == 0) return (n + 10) / 20;
  return (n + 9) / 2 % 10;
}

void solve() {
  int N;
  cin >> N;
  cout << champernowne(N) << endl;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
  getchar();
}