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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
public class Main
{
    public static void main(String[] args)
    {
        int count = 0;
        boolean sw = false;
        int max = Integer.MIN_VALUE;
        int min = Integer.MAX_VALUE;
        double dMax = Double.MIN_VALUE;
        double dMin = Double.MAX_VALUE;
        //
        Scanner sc = new Scanner(System.in);
        //int n = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();

        List<Integer> aList = new ArrayList<>();
        List<Integer> bList = new ArrayList<>();

        for (int i=0;i<=9;++i)
        {
            int aTax = (int)Math.floor((a+0.1*i)/0.08);
            int bTax = (int)Math.floor((b+0.1*i)/0.1);
            aList.add(aTax);
            bList.add(bTax);
        }

//        System.out.print("alist = <");
//        for (int i:aList) System.out.print(i+",");
//        System.out.println(">");
//
//        System.out.print("blist = <");
//        for (int i:bList) System.out.print(i+",");
//        System.out.println(">");

        int an1 = -1;
        for (int i:aList)
        {
            if (bList.contains(i))
            {
                an1 = i;
                break;
            }
        }

        System.out.println(an1);
        sc.close();
    }
}