Problem:
Score : 300 points

Problem Statement

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

Output

If there is a price that satisfies the condition, print an integer representing the lowest such price; otherwise, print -1.

Sample Input 1

2 2

Sample 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.

Sample Input 2

8 10

Sample 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.

Sample Input 3

19 99

Sample Output 3

-1

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

Solution in C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)


using System;
using System.Linq;
using System.Windows.Markup;

class IDONTKNOWCSHARP
{

    public static void Main()
    {
        string[] str = Console.ReadLine().Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);

        int A = int.Parse(str[0]);
        int B = int.Parse(str[1]);

        int As = (int)(A / 1.08);
        int Bs = (int)(B / 1.1);

        if (As < 0 && Bs > 0)
        {
            Console.WriteLine(Bs);
            return;
        }
        else if (As > 0 && Bs < 0)
        {
            Console.WriteLine(As);
            return;
        }
        else if (As < 0 && Bs < 0)
        {
            Console.WriteLine(-1);
            return;
        }

        if (As > Bs)
        {
            Console.WriteLine(Bs);
        }
        else
        {
            Console.WriteLine(As);

        }
    }


}