{"raw_statement":[{"iden":"problem statement","content":"Find the price of a product before tax such that, when the consumption tax rate is $8$ percent and $10$ percent, the amount of consumption tax levied on it is $A$ yen and $B$ yen, respectively. (Yen is the currency of Japan.)\nHere, the price before tax must be a positive integer, and the amount of consumption tax is rounded down to the nearest integer.\nIf multiple prices satisfy the condition, print the lowest such price; if no price satisfies the condition, print `-1`."},{"iden":"constraints","content":"*   $1 \\leq A \\leq B \\leq 100$\n*   $A$ and $B$ are integers."},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$A$ $B$"},{"iden":"sample input 1","content":"2 2"},{"iden":"sample output 1","content":"25\n\nIf the price of a product before tax is $25$ yen, the amount of consumption tax levied on it is:\n\n*   When the consumption tax rate is $8$ percent: $\\lfloor 25 \\times 0.08 \\rfloor = \\lfloor 2 \\rfloor = 2$ yen.\n*   When the consumption tax rate is $10$ percent: $\\lfloor 25 \\times 0.1 \\rfloor = \\lfloor 2.5 \\rfloor = 2$ yen.\n\nThus, the price of $25$ yen satisfies the condition. There are other possible prices, such as $26$ yen, but print the minimum such price, $25$."},{"iden":"sample input 2","content":"8 10"},{"iden":"sample output 2","content":"100\n\nIf the price of a product before tax is $100$ yen, the amount of consumption tax levied on it is:\n\n*   When the consumption tax rate is $8$ percent: $\\lfloor 100 \\times 0.08 \\rfloor = 8$ yen.\n*   When the consumption tax rate is $10$ percent: $\\lfloor 100 \\times 0.1 \\rfloor = 10$ yen."},{"iden":"sample input 3","content":"19 99"},{"iden":"sample output 3","content":"\\-1\n\nThere is no price before tax satisfying this condition, so print `-1`."}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}