{"raw_statement":[{"iden":"problem statement","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."},{"iden":"constraints","content":"*   All values in input are integers.\n*   $0 \\leq A,\\ B \\leq 10^9$\n*   $A$ and $B$ are distinct."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$A$ $B$"},{"iden":"sample input 1","content":"2 16"},{"iden":"sample output 1","content":"9\n\n$|2 - 9| = 7$ and $|16 - 9| = 7$, so $9$ satisfies the condition."},{"iden":"sample input 2","content":"0 3"},{"iden":"sample output 2","content":"IMPOSSIBLE\n\nNo integer satisfies the condition."},{"iden":"sample input 3","content":"998244353 99824435"},{"iden":"sample output 3","content":"549034394"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}