def alternate_elements(list1):
    
    result=[]
    for item in list1[::2]:
        result.append(item)
    return result 
def is_not_prime(n):
    import math
    
    result = False
    for i in range(2,int(math.sqrt(n)) + 1):
        if n % i == 0:
            result = True
    return result