# import necessary libraries
import pandas as pd

# define your series
ser1 = pd.Series([1, 2, 3, 4, 5])
ser2 = pd.Series([4, 5, 6, 7, 8])

# use - operator after set() conversion
result = set(ser1.values) - set(ser2.values)

# print the result
print(*result, sep = '\n')