{"raw_statement":[{"iden":"statement","content":"You have a list of numbers. You want to figure out how many distinct (different) numbers are in the list. For example, the list _[1, 2, 3, 4, 4, 5, 5]_ has 5 distinct numbers.\n\nThe first line of input contains a single positive integer $n$: the number of items in the list. The next line contains $n$ space-separated integers: the list.\n\nOutput a single positive integer $d$: the number of distinct numbers in the list.\n\n"},{"iden":"input","content":"The first line of input contains a single positive integer $n$: the number of items in the list. The next line contains $n$ space-separated integers: the list."},{"iden":"output","content":"Output a single positive integer $d$: the number of distinct numbers in the list."},{"iden":"examples","content":"Input5\n2 2 3 5 6\nOutput4\nInput4\n1 2 3 4\nOutput4\n"}],"translated_statement":null,"sample_group":[],"show_order":[],"formal_statement":"**Definitions**  \nLet $ n \\in \\mathbb{Z}^+ $ be the number of elements in the list.  \nLet $ A = (a_1, a_2, \\dots, a_n) $ be a sequence of integers.\n\n**Constraints**  \n$ n \\geq 1 $, and $ a_i \\in \\mathbb{Z} $ for all $ i \\in \\{1, \\dots, n\\} $.\n\n**Objective**  \nCompute $ d = \\left| \\{ a_1, a_2, \\dots, a_n \\} \\right| $, the cardinality of the set of distinct elements in $ A $.","simple_statement":"Count how many different numbers are in the list.","has_page_source":false}