import math

def is_prime(n):
    """
    via https://qiita.com/srtk86/items/874639e361917e5016d4
    """
    if n == 1:
        return False
    for k in range(2, int(math.sqrt(n)) + 1):
        if n % k == 0:
            return False
    return True

N = int(input())

i = 1
count = 1
while True:
    if i == 100000:
        break
    if not is_prime(i):
        if count == N:
            print(i)
            break
        count += 1
    i += 1