Tax Increase

AtCoder

IDabc158_c

Time2000ms

Memory256MB

Difficulty—

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.) Here, the price before tax must be a positive integer, and the amount of consumption tax is rounded down to the nearest integer. If multiple prices satisfy the condition, print the lowest such price; if no price satisfies the condition, print `-1`. ## Constraints * $1 \leq A \leq B \leq 100$ * $A$ and $B$ are integers. ## Input Input is given from Standard Input in the following format: $A$ $B$ [samples]

Samples

Input #1

2 2

Output #1

25

If the price of a product before tax is $25$ yen, the amount of consumption tax levied on it is:

*   When the consumption tax rate is $8$ percent: $\lfloor 25 \times 0.08 \rfloor = \lfloor 2 \rfloor = 2$ yen.
*   When the consumption tax rate is $10$ percent: $\lfloor 25 \times 0.1 \rfloor = \lfloor 2.5 \rfloor = 2$ yen.

Thus, the price of $25$ yen satisfies the condition. There are other possible prices, such as $26$ yen, but print the minimum such price, $25$.

Input #2

8 10

Output #2

100

If the price of a product before tax is $100$ yen, the amount of consumption tax levied on it is:

*   When the consumption tax rate is $8$ percent: $\lfloor 100 \times 0.08 \rfloor = 8$ yen.
*   When the consumption tax rate is $10$ percent: $\lfloor 100 \times 0.1 \rfloor = 10$ yen.

Input #3

19 99

Output #3

\-1

There is no price before tax satisfying this condition, so print `-1`.

API Response (JSON)

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    "name": "Tax Increase",
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      "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",
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    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
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    "difficulty": "None",
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      "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 i...",
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