def is_prime(n):
    if n <= 1:
        return False
    if n <= 3:
        return True
    if n % 2 == 0 or n % 3 == 0:
        return False
    i = 5
    while i * i <= n:
        if n % i == 0 or n % (i + 2) == 0:
            return False
        i += 6
    return True

def find_prime_numbers():
    prime_numbers = []
    for num in range(500, 1000):
        if num % 10 == 5 and str(num)[0] == '5':  
            if is_prime(num):
                prime_numbers.append(num)
    return prime_numbers

result = find_prime_numbers()
print("all prime numbers having 3 digits and starting with 5:")
print(result)