{"problem":{"name":"Tax Increase","description":{"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 i","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc158_c"},"statements":[{"statement_type":"Markdown","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`.\n\n## Constraints\n\n*   $1 \\leq A \\leq B \\leq 100$\n*   $A$ and $B$ are integers.\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":"abc158_c","tags":[],"sample_group":[["2 2","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, $25$."],["8 10","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."],["19 99","\\-1\n\nThere is no price before tax satisfying this condition, so print `-1`."]],"created_at":"2026-03-03 11:01:14"}}