from math import *

def Sieve(n):
    lst = [True] * (n + 1)
    S = [1]
    for i in range(2, ceil(sqrt(n)) + 1):
        if lst[i]:
            for j in range(2 * i, n + 1, i):
                lst[j] = False
    for i in range(100000, n + 1):
        if lst[i]:
            S.append(i)
    return S

N = int(input())
S = Sieve(105050)
print(S[N - 1])