{"problem":{"name":"Make a Rectangle","description":{"content":"We have $N$ sticks with negligible thickness. The length of the $i$\\-th stick is $A_i$. Snuke wants to select four different sticks from these sticks and form a rectangle (including a square), using t","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"arc081_a"},"statements":[{"statement_type":"Markdown","content":"We have $N$ sticks with negligible thickness. The length of the $i$\\-th stick is $A_i$.\nSnuke wants to select four different sticks from these sticks and form a rectangle (including a square), using the sticks as its sides. Find the maximum possible area of the rectangle.\n\n## Constraints\n\n*   $4 \\leq N \\leq 10^5$\n*   $1 \\leq A_i \\leq 10^9$\n*   $A_i$ is an integer.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$\n$A_1$ $A_2$ ... $A_N$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"arc081_a","tags":[],"sample_group":[["6\n3 1 2 4 2 1","2\n\n$1 \\times 2$ rectangle can be formed."],["4\n1 2 3 4","0\n\nNo rectangle can be formed."],["10\n3 3 3 3 4 4 4 5 5 5","20"]],"created_at":"2026-03-03 11:01:13"}}