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.io.*;
import java.util.*;
import java.util.ArrayList;
 
class Main
{
  public static void main (String[] arg)
  {
    Scanner scan = new Scanner(System.in);
       
    int tax_8 = Integer.parseInt(scan.next()); //整数    8
    int tax_10 = Integer.parseInt(scan.next()); //整数　　10
    
    ArrayList<Integer> array_8 = new ArrayList<>();
    ArrayList<Integer> array_10 = new ArrayList<>();
    
    int ans = -1;
    
    for(int i = 0; i < 1262; i++){
      if(Math.floor(i * 0.08) == tax_8){
        array_8.add(i);
      }
    }
    
    for(int i = 0; i < 1010; i++){
      if(Math.floor(i * 0.1) == tax_10){
        array_10.add(i);
      }
    }
 
    loop:
    for(int i = 0; i <array_8.size(); i++){
      for(int j = 0; j <array_10.size(); j++){
        if(array_8.get(i) == array_10.get(j)){
          ans = array_8.get(i);
          break loop; 
        }
      }
    }
    System.out.println(ans);
  }
}