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 (Python):
import sys
input = sys.stdin.readline

def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))

def main():
    mod=10**9+7
    a,b=MI()
    ans=-1
    for i in range(10000):
        aa=int(i*0.08)
        bb=i//10
        if a==aa and b==bb:
            ans=i
            break
    print(ans)

main()

Solution (Python):
a,b = map(int,input().split())
for i in range(10000):
    if int(i * 0.08) == a and int(i * 0.1) == b:
        print(i)
        exit()
print(-1)

Solution (Python):
a, b = map(int, input().split())
for i in range(1, 1010):
	if int(i * 0.08) == a and int(i * 0.1) == b:
		print(i)
		break
else:
	print(-1)

Solution (Python):
a, b= map(int, input().split())
ans = -1
for i in range(100000):
    if int(i*0.08) == a and int(i*0.1) == b:
        ans = i
        break

print(ans)