import random

def isPrimeMillerRabin(n, k=3):
    if n <= 1:
        return False
    if n == 2 or n == 3:
        return True
    if n % 2 == 0:
        return False

    r, d = 0, n - 1
    while d % 2 == 0:
        r += 1
        d //= 2

    # Perform Miller-Rabin test k times
    for _ in range(k):
        a = random.randint(2, n - 2)
        x = pow(a, d, n)

        if x == 1 or x == n - 1:
            continue

        for _ in range(r - 1):
            x = pow(x, 2, n)
            if x == n - 1:
                break
        else:
            return False  

    return True  # Likely to be prime


N = float(input()) / 100
count = 0
i = 3  
spiral_size = 1

while True:
    for j in range(4):
        num = i**2 - (i - 1) * j
        if isPrimeMillerRabin(num):
            count += 1
            
    spiral_size += 4
    proportion = count / spiral_size

    if proportion < N:
        break

    i += 2  

print(i)

 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;
    }
}

import random

def isprime(n):
    '''Miller rabbin'''
    if n in [2,3,5,7]:
        return True
    
    d=n-1
    s=0
    while not d%2:
        s+=1
        d=d//2
    for i in range(4):
        a=random.randint(2,n-1)
        x=pow(a,d,n)
        if x not in [1,n-1]:
            active=True
            for r in range(s):
                if pow(x,2**r,n) == n-1:
                    active=False
                    break
            if active:
                return False
    return True

        
            
n=int(input())
primes_count=0
i=3
last_no=1

while True:
    for j in range(4):
        last_no+=i-1
        if j!=3 and isprime(last_no):
            primes_count+=1
    
    primes_percentage=primes_count/(1+2*(i-1))*100
    if primes_percentage<n:
        print(i)
        break
    i+=2