set_difference.py

#!/bin/python3

# Set .difference() Operation Challenge Solution
# problem link: https://www.hackerrank.com/challenges/py-set-difference-operation/problem
# Author: Audity Ghosh
# Date: 30 January 2020
# Description:
# This script calculates the total number of students who have subscribed to only the
# English newspaper using the set .difference() operation.

# Enter your code here. Read input from STDIN. Print output to STDOUT
n = int(input())  # Read number of students who subscribed to the English newspaper
data1 = set(list(map(int, input().split(' '))))  # Roll numbers of students subscribed to English newspaper
t = int(input())  # Read number of students who subscribed to the French newspaper
data2 = set(list(map(int, input().split(' '))))  # Roll numbers of students subscribed to French newspaper

# Find the difference between the English and French subscription sets (students subscribed only to English)
s = set(data1.difference(data2))

# Output the total number of students who have subscriptions to only the English newspaper
print(len(s))