import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
          Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        scanner.close();

        int primesCount = 0;
        int i = 3;
        int lastNumber = 1;

        while (true) {
            for (int j = 0; j < 4; j++) {
                lastNumber += i - 1;
                if (j != 3 && isPrime(lastNumber)) {
                    primesCount++;
                }
            }

            double primesPercentage = (double) primesCount / (1 + 2 * (i - 1)) * 100;
            if (primesPercentage < n) {
                System.out.println(i);
                break;
            }
            i += 2;
        }
    }

    public static boolean isPrime(int n) {
        if (n <= 1) {
            return false;
        }
        if (n <= 3) {
            return true;
        }
        if (n % 2 == 0 || n % 3 == 0) {
            return false;
        }

        int d = n - 1;
        int s = 0;
        while (d % 2 == 0) {
            s++;
            d /= 2;
        }

        Random random = new Random();
        for (int i = 0; i < 4; i++) {
            int a = random.nextInt(n - 2) + 2;
            int x = modPow(a, d, n);
            if (x != 1 && x != n - 1) {
                boolean active = true;
                for (int r = 0; r < s; r++) {
                    x = modPow(x, 2, n);
                    if (x == n - 1) {
                        active = false;
                        break;
                    }
                }
                if (active) {
                    return false;
                }
            }
        }
        return true;
    }

    public static int modPow(int base, int exponent, int mod) {
        int result = 1;
        base %= mod;
        while (exponent > 0) {
            if (exponent % 2 == 1) {
                result = (int) ((long) result * base % mod);
            }
            base = (int) ((long) base * base % mod);
            exponent /= 2;
        }
        return result;
    }
}