[pyar] Fwd: Monk in the land of Pokemons! (Reto hackeearth)

[José de Jesus Marquez Rangel]

Saludos.

Alguien que tenga dominio en el ingles me puede ayudar a entender  el reto.
Para crear la solución en python.

De verdad mi ingles es muy básico y me cuesta un poco entender.


Monk has to visit a land where strange creatures, known as Pokemons, roam
around in the wild. Each Pokemon in the land will attack any visitor. They
can only be pacified by feeding them their favorite food.

The Pokemon of type *X* eats one food item of type *X*.

Monk knows that he will encounter *N* ponds on the way. At each pond, he
will find a food item and then encounter a Pokemon. The *i*'th pond has the
food item of type *Ai* and the Pokemon of type *Bi*.

The monk can feed the item at the *i*'th pond to the Pokemon at the pond if
the type matches. Monk may have to carry some food items with him before
leaving so as to feed all the Pokemons. Help him find the *number* of items
he must carry, to be to able to pass through the land safely.

*Input*:
The first line contains *T*, denoting the number of test cases. Then, *T*
test cases follow.
The first line of each test case contains an integer *N*. Then, *N* lines
follow.
Each line consists of 2 space-separated integers *Ai* and *Bi*.

*Output*: For each test case, print the answer in a new line.

*Constraints*:
1 ≤ *T* ≤ 10
1 ≤ *N* ≤ 105
1 ≤ *Ai*, *Bi* ≤ 106
------------------------------
Sample Input
(Plaintext Link)
<https://he-s3.s3.amazonaws.com/media/hackathon/code-monk-hashing/problems/monk-in-the-land-of-pokemons/420ca8da-2-sample-input-420ca57.txt?Signature=jACN9QPChJd%2Fz2iuc7GiJ%2Btehq8%3D&Expires=1453306426&AWSAccessKeyId=AKIAJLE6MUHDYS3HN6YQ>

1
5
1 1
2 2
3 4
4 3
2 4

Sample Output
(Plaintext Link)
<https://he-s3.s3.amazonaws.com/media/hackathon/code-monk-hashing/problems/monk-in-the-land-of-pokemons/4221bc70-2-sample-output-4221b91.txt?Signature=p2FXvCbOFhYBVLhvHhs%2F9J5B2IU%3D&Expires=1453306426&AWSAccessKeyId=AKIAJLE6MUHDYS3HN6YQ>

1

Explanation

At First Pond he gets item of type1 and feeds it to the Pokemon of type1.
At Second Pond he gets item of type 2 and feeds it to the Pokemon of type2.
At Third Pond he gets item of type 3 ,but the Pokemon is of type4 . Hence,
he has to bring a food item of type 4 with him.
At Fourth Pond he gets item of type 4. He already has a item of type 3 and
feeds it to the Pokemon.
At Fifth Pond he gets items of type 2. He already has a item of type 4 and
feeds it to the Pokemon at this pond.
------------------------------
------------ próxima parte ------------
Se ha borrado un adjunto en formato HTML...
URL: <http://listas.python.org.ar/pipermail/pyar/attachments/20160120/8953dd93/attachment-0001.html>