#include <bits/stdc++.h>

using namespace std;

int main() {
    int d;
    
    cin >> d;
    
    if (d < 10) {
        cout << d << endl;
    } else {
        if (d % 2 == 0) {
            d -= 9;
            d = d / 20 + 1;
        } else {
            d -= 10;
            d = (d % 20) / 2;
        }
    }
    
    cout << d << endl;
    
    return 0;
}