input: Write a function to print the numbers from 1 to 50, but for multiples of 3 print "Fizz" instead of the number, for multiples of 5 print "Buzz" instead of the number, and for multiples of both 3 and 5 print "FizzBuzz". If the parameter is not 50, then it should print "Invalid input".
  assert fizz_buzz(50)==None
  assert fizz_buzz(15)==None
  assert fizz_buzz(0)=="Invalid input"
  assert fizz_buzz(100)=="Invalid input"
output: def fizz_buzz(n):
      if n != 50:
          print("Invalid input")
          return
      for i in range(1, 51):
          if i % 3 == 0 and i % 5 == 0:
              print("FizzBuzz")
          elif i % 3 == 0:
              print("Fizz")
          elif i % 5 == 0:
              print("Buzz")
          else:
              print(i)