Matchmaking :
Difficulty Level : Easy
Submissions : 673
Asked In :
Marks :10
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Intuit has $$$N$$$ experts where each expert knows exactly one language and one topic (represented by pair $$$x$$$ and $$$y$$$). We have $$$M$$$ customers where each customer has exactly one language and one topic which they want the expert to match with.
If a customer doesn't match with an expert then they are unhappy.
Find total number of unhappy customers after assigning.
First line of the input contains two integers, $$$N$$$ (1 $$$\leq$$$ $$$N$$$ $$$\leq$$$ $$$1e5$$$) and $$$M$$$ (1 $$$\leq$$$ $$$M$$$ $$$\leq$$$ $$$1e5$$$)
Next N lines contain the language and topic known by each expert, represented by two integers $$$x$$$ (1 $$$\leq$$$ $$$x$$$ $$$\leq$$$ $$$1e5$$$) and $$$y$$$ (1 $$$\leq$$$ $$$y$$$ $$$\leq$$$ $$$1e5$$$)
Next N lines contain the language and topic customer wants to learn, represented by two integers $$$x$$$ (1 $$$\leq$$$ $$$x$$$ $$$\leq$$$ $$$1e5$$$) and $$$y$$$ (1 $$$\leq$$$ $$$y$$$ $$$\leq$$$ $$$1e5$$$) .
Output a single integer, the number of unhappy customers.
3 2 1 2 2 1 1 1 1 2 4 4
1
3 2 1 2 2 1 1 1 1 2 1 1
0
1 2 1 2 1 2 1 1
1
