import math
def main():
    n = int(input())
    a = [1]
    for i in range(100001, 500000):
        flg = True
        for j in (2,math.sqrt(i) + 1):
            if i % j == 0:
                flg = False
                break
        if flg:
           a.append(i * i)

    a.sort()
    print(a[n - 1])
main()