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 (3.8.2) (judge verdict: Wrong Answer)

import math

a,b = map(int,input().split())

n = math.floor(a / 0.08)
m = math.floor(b / 0.1)
n2 = n + 1
m2 = m + 1

p = math.floor(n * 0.08)
q = math.floor(n * 0.1)
x = math.floor(m * 0.08)
y = math.floor(m * 0.1)
p2 = math.floor(n2 * 0.08)
q2 = math.floor(n2 * 0.1)
x2 = math.floor(m2 * 0.08)
y2 = math.floor(m2 * 0.1)

if p == a and q == b and x == a and y == b:
    print(min(n,m))
elif p == a and q == b:
    print(n)
elif x == a and y == b:
    print(m)
if p2 == a and q2 == b and x2 == a and y2 == b:
    print(min(n2,m2))
elif p2 == a and q2 == b:
    print(n2)
elif x2 == a and y2 == b:
    print(m2)
else:
    print(-1)