def main():
    n = int(input('Enter n: '))
    count = (- 1)
    curr = 0
    while (count < n):
        curr += 1
        if is_prime_power(curr):
            count += 1
    print(curr)
def main():
    n = int(input('Enter n: '))
    count = (- 1)
    curr = 0
    while (count < n):
        curr += 1
        if is_prime_power(curr):
            count += 1
    print(curr)