{"trustable":false,"sections":[{"title":"题面:","value":{"format":"MD","content":"出题人已经写好n个题目并且想使用其中的k个题目生成一个比赛。每个题目有一个难度等级,如果这场比赛的每个题目的难度等级都不一样说明这个比赛是合法的。\n计算一下出题人可以出多少个比赛。只要两个比赛至少有一个题目其中一场比赛中没有而另一个比赛有,则说明这两个比赛是不同的。\n输出答案取模998,244,353。"}},{"title":"输入:","value":{"format":"MD","content":"一行输入包含两个整数n和k(1\u003c\u003dk\u003c\u003dn\u003c\u003d1000)\n下一行包含n个整数代表不同题目的难度等级。难度等级都在[1,10^9]范围内。"}},{"title":"输出:","value":{"format":"MD","content":"输出可能的比赛数,取模998,244,353。"}},{"title":"样例输入:","value":{"format":"MD","content":"5 2 \n1 2 3 4 5"}},{"title":"样例输出:","value":{"format":"MD","content":"10"}},{"title":"样例输入:","value":{"format":"MD","content":"5 2 \n1 1 1 2 2"}},{"title":"样例输出:","value":{"format":"MD","content":"6"}},{"title":"样例输入:","value":{"format":"MD","content":"12 5 \n3 1 4 1 5 9 2 6 5 3 5 8"}},{"title":"样例输出:","value":{"format":"MD","content":"316"}}]}