#include <iostream>

#include <string>

using namespace std;

int main() {
    string S;
    for (int i = 1; i < 100; ++i) {
        for (char c : to_string(i)) {
            S.push_back(c);
        }
    }

    int D;
    cin >> D;
    cout << S[D - 1] << endl;
    return 0;
}