#include<bits/stdc++.h>
#define rep(i, x) for(ll i = 0; i < x; i++)
#define rep2(i, x) for(ll i = 1; i <= x; i++)
#define all(a) (a).begin(),(a).end()
using ll = long long;
using ld = long double;
using namespace std;
signed main() {
    ll n, cnt = 0; cin >> n;
	rep2(i, 100) {
		if (i <= 9) {
			if (cnt + 1 == n) { cout << i << endl; return 0; }
			cnt++;
		}
		else {
			if (cnt + 1 == n) { cout << i / 10 << endl; return 0; }
			if (cnt + 2 == n) { cout << i % 10 << endl; return 0; }
			cnt += 2;
		}
	}
	return 0;
}