Write a program that counts the number of prime numbers less than a given number. The program should take an integer as input and output the number of primes less than the input.
Example:
Input: 10 Output: 4 Input: 20 Output: 8
A prime number is a natural number greater than 1 that has no divisors other than 1 and itself. You may need to implement a helper function to check if a number is prime.
def is_prime(n): if n < 2: return False for i in range(2, int(n**0.5) + 1): if n % i == 0: return False return True def count_primes(num): count = 0 for i in range(2, num): if is_prime(i): count += 1 return count print(count_primes(10)) # Outputs: 4 print(count_primes(20)) # Outputs: 8
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