def is_power_of_four(n):
 
  return n > 0 and (n & (n - 1)) == 0 and (n - 1) % 3 == 0

# Example 1
n = 16
print(is_power_of_four(n)) 

# Example 2
n = 5
print(is_power_of_four(n))

# Example 3
n = 1
print(is_power_of_four(n))