{"raw_statement":[{"iden":"problem statement","content":"Takahashi is playing with $N$ cards.\nThe $i$\\-th card has an integer $X_i$ on it.\nTakahashi is trying to create as many pairs of cards as possible satisfying one of the following conditions:\n\n*   The integers on the two cards are the same.\n*   The sum of the integers on the two cards is a multiple of $M$.\n\nFind the maximum number of pairs that can be created.\nNote that a card cannot be used in more than one pair."},{"iden":"constraints","content":"*   $2≦N≦10^5$\n*   $1≦M≦10^5$\n*   $1≦X_i≦10^5$"},{"iden":"input","content":"The input is given from Standard Input in the following format:\n\n$N$ $M$\n$X_1$ $X_2$ $...$ $X_N$"},{"iden":"sample input 1","content":"7 5\n3 1 4 1 5 9 2"},{"iden":"sample output 1","content":"3\n\nThree pairs $(3,2), (1,4)$ and $(1,9)$ can be created.\nIt is possible to create pairs $(3,2)$ and $(1,1)$, but the number of pairs is not maximized with this."},{"iden":"sample input 2","content":"15 10\n1 5 6 10 11 11 11 20 21 25 25 26 99 99 99"},{"iden":"sample output 2","content":"6"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}