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 Python (3.4.3) (judge verdict: Wrong Answer)

import math
tax1,tax2 = map(int,input().split())
tax_max1 = tax1+1 
if tax_max1%0.08 != 0:
    subtraction1 = int((tax_max1/0.08)) - math.ceil(tax1/0.08)
    store1 = []
    beggining1 = math.ceil(tax1/0.08)
    for num in range(subtraction1+1):
        price = beggining1 + num
        store1.append(price)
else:
    subtraction1 = int((tax_max1/0.08)-1) - math.ceil(tax1/0.08)
    store1 = []
    beggining1 = math.ceil(tax1/0.08)
    for num in range(subtraction1+1):
        price = beggining1 + num
        store1.append(price)
tax_max2 = tax2+1
subtraction2 = int((tax_max2/0.10)-1) - math.ceil(tax2/0.10)
store2 = []
beggining2 = math.ceil(tax2/0.10)
for num in range(subtraction2+1):
    price = beggining2 + num
    store2.append(price)

list3 = [value1 for value1 in store1 if value1 in store2]
if len(list3)>0:
    print(list3[0])
else:
    print(-1)