def is_prime(x):
    for p in range(3, int(x ** 0.5) + 1, 2):
        if x % p == 0:
            return False
    return True

def search(percent):
    n = 7
    prime = 8
    total = 13
    while prime / total > percent:
        n += 2
        total += 4
        for num in range((n - 3) * n + 3, n * n - 1, n - 1):
            if is_prime(num):
                prime += 1
    return n

print(search(0.1))