Set .difference() Operation in python3 code example

Example: Set .difference() Operation in python3

# Enter your code here. Read input from STDIN. Print output to STDOUT
n1 = int(input())
set_1 = set(map(int,input().split()))
n2 = int(input())
set_2 = set(map(int,input().split()))
print(len(set_1-set_2))