{"raw_statement":[{"iden":"problem statement","content":"You are given positive integers $X$ and $Y$. If there exists a positive integer not greater than $10^{18}$ that is a multiple of $X$ but not a multiple of $Y$, choose one such integer and print it. If it does not exist, print $-1$."},{"iden":"constraints","content":"*   $1 ≤ X,Y ≤ 10^9$\n*   $X$ and $Y$ are integers."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$X$ $Y$"},{"iden":"sample input 1","content":"8 6"},{"iden":"sample output 1","content":"16\n\nFor example, $16$ is a multiple of $8$ but not a multiple of $6$."},{"iden":"sample input 2","content":"3 3"},{"iden":"sample output 2","content":"\\-1\n\nA multiple of $3$ is a multiple of $3$."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}