import java.io.BufferedReader;
import java.io.InputStreamReader;

/**
 * ツェラーの公式だかってやつで年月日が分かると曜日が分かるやつ
 *
 */
public class No087 {

    private static final int WED = 3;

    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(
                    System.in));
            int y_end = Integer.parseInt(br.readLine());
            int Y;
            int m = 7;
            int d = 23;
            int C;
            int ganma;
            int D = 0;
            int count = 0;
            for (int i = 2015; i <= y_end; i++) {
                Y = i % 100;
                C = i / 100;
                ganma = -2 * C + C / 4;
                D = (d + ((26 * (m + 1)) / 10 + Y + Y / 4 + ganma + 5)) % 7 + 1;
                if (D == WED) {
                    count++;
                }
            }

            System.out.println(count);
        } catch (Exception e) {
            System.err.println("Error:" + e.getMessage());
        }
    }

}