{"problem":{"name":"Harmony","description":{"content":"We have two distinct integers $A$ and $B$. Print the integer $K$ such that $|A - K| = |B - K|$. If such an integer does not exist, print `IMPOSSIBLE` instead.","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc135_a"},"statements":[{"statement_type":"Markdown","content":"We have two distinct integers $A$ and $B$.\nPrint the integer $K$ such that $|A - K| = |B - K|$.\nIf such an integer does not exist, print `IMPOSSIBLE` instead.\n\n## Constraints\n\n*   All values in input are integers.\n*   $0 \\leq A,\\ B \\leq 10^9$\n*   $A$ and $B$ are distinct.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$A$ $B$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc135_a","tags":[],"sample_group":[["2 16","9\n\n$|2 - 9| = 7$ and $|16 - 9| = 7$, so $9$ satisfies the condition."],["0 3","IMPOSSIBLE\n\nNo integer satisfies the condition."],["998244353 99824435","549034394"]],"created_at":"2026-03-03 11:01:14"}}