{"raw_statement":[{"iden":"problem statement","content":"Takahashi has $N$ sticks that are distinguishable from each other. The length of the $i$\\-th stick is $L_i$.\nHe is going to form a triangle using three of these sticks. Let $a$, $b$, and $c$ be the lengths of the three sticks used. Here, all of the following conditions must be satisfied:\n\n*   $a < b + c$\n*   $b < c + a$\n*   $c < a + b$\n\nHow many different triangles can be formed? Two triangles are considered different when there is a stick used in only one of them."},{"iden":"constraints","content":"*   All values in input are integers.\n*   $3 \\leq N \\leq 2 \\times 10^3$\n*   $1 \\leq L_i \\leq 10^3$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$\n$L_1$ $L_2$ $...$ $L_N$"},{"iden":"sample input 1","content":"4\n3 4 2 1"},{"iden":"sample output 1","content":"1\n\nOnly one triangle can be formed: the triangle formed by the first, second, and third sticks."},{"iden":"sample input 2","content":"3\n1 1000 1"},{"iden":"sample output 2","content":"0\n\nNo triangles can be formed."},{"iden":"sample input 3","content":"7\n218 786 704 233 645 728 389"},{"iden":"sample output 3","content":"23"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}