import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class PCR {

    static BufferedReader br;
    static PrintWriter out;
    static StringTokenizer st;

    public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(new OutputStreamWriter(System.out));

        double p = readDouble();
        double min = 1;
        int N = 1;
        for (int i = 2; i <= 16; i++) {
            double P = Math.pow(1 - p, i);
            double ET = 1 * P + i * (1 - P);
            double ratio = ET / i;
            if (ratio < min) {
                min = ratio;
                N = i;
            }
        }

        out.println(N);

        out.close();
    }

    static String next() throws IOException {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    }

    static long readLong() throws IOException {
        return Long.parseLong(next());
    }

    static int readInt() throws IOException {
        return Integer.parseInt(next());
    }

    static double readDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static char readCharacter() throws IOException {
        return next().charAt(0);
    }

    static String readLine() throws IOException {
        return br.readLine().trim();
    }
}