OK, lets check it again... I'm quoting puzzle statements:
First it says:
War is a card game played between two players. Each player gets a variable number of cards of the beginning of the game: that's the player's deck. Cards are placed face down ON TOP OF EACH DECK.
Then in the input section:
Line 1: the number N of cards for player one.
N next lines: the cards of player one.
Next line: the number M of cards for player two.
M next lines: the cards of player two.
Here you never mention the fact that input is premade deck, and not just cards as you give them in a card game, as any human with a sense of logic will assume.
So, I recommend you to not shield defects of this puzzle's description by implying my "reading skills", and rather edit this puzzle description to eliminate this kind of misunderstandings in the future.
Look, I'm not trying to insult you (had a very bad mood after wasting few hours on the time of 1st post), I'm just trying to help this site get better, that's all.