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){
        Scanner scan = new java.util.Scanner(System.in);
        int a = scan.nextInt();
        int b = scan.nextInt();
        int[] c = new int[13];
        int[] d = new int[11];
        int minc = Integer.MAX_VALUE;
        int mind = Integer.MAX_VALUE;
        for(int i = 0; i <= 12; i++){
            if(a % 2 == 0){
                c[i] = (int) (a * 12.5 + i);
            }else{
                c[i] = (int) (a * 12.5 + i) + 1;
            }
            if(c[i] < minc){
                minc = c[i];
            }
            System.out.print(c[i] + " ");
        }
        for(int i = 0; i <= 9; i++){
            if(b % 10 == 0){
                d[i] = (int) (b * 10 + i);
            }else{
                d[i] = (int) (b * 10 + i) + 1;
            }
            if(d[i] < mind){
                mind = d[i];
            }
            System.out.print(d[i] + " ");
        }
        if(Math.abs((int) (a * 12.5) - (int) (b * 10)) > 10){
            System.out.println(-1);
        }else if(minc <= mind){
            System.out.println(mind);
        }else{
            System.out.println(minc);
        }
    }
}