{"raw_statement":[{"iden":"problem statement","content":"We have $N$ cards. A number $a_i$ is written on the $i$\\-th card.  \nAlice and Bob will play a game using these cards. In this game, Alice and Bob alternately take one card. Alice goes first.  \nThe game ends when all the cards are taken by the two players, and the score of each player is the sum of the numbers written on the cards he/she has taken. When both players take the optimal strategy to maximize their scores, find Alice's score minus Bob's score."},{"iden":"constraints","content":"*   $N$ is an integer between $1$ and $100$ (inclusive).\n*   $a_i \\ (1 \\leq i \\leq N)$ is an integer between $1$ and $100$ (inclusive)."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$a_1$ $a_2$ $a_3$ $...$ $a_N$"},{"iden":"sample input 1","content":"2\n3 1"},{"iden":"sample output 1","content":"2\n\nFirst, Alice will take the card with $3$. Then, Bob will take the card with $1$. The difference of their scores will be $3$ - $1$ = $2$."},{"iden":"sample input 2","content":"3\n2 7 4"},{"iden":"sample output 2","content":"5\n\nFirst, Alice will take the card with $7$. Then, Bob will take the card with $4$. Lastly, Alice will take the card with $2$. The difference of their scores will be $7$ - $4$ + $2$ = $5$. The difference of their scores will be $3$ - $1$ = $2$."},{"iden":"sample input 3","content":"4\n20 18 2 18"},{"iden":"sample output 3","content":"18"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}