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):
A,B=[int(i) for i in input().split(" ")]

for i in range(1010):
    if int(i*0.08)==A and int(i*0.1)==B:
        print(i)
        break
else:
    print(-1)

Solution (Python):
import math
a,b = map(int,input().split())
c = b - a
if c < 0:
    print(-1)
    exit()
d = math.floor(c / 2 * 100)
for i in range(max(0, d - 10000), d + 10000):
    if math.floor(i * 1.08) - i == a and math.floor(i * 1.1) - i == b:
        print(i)
        exit()
print(-1)

Solution (Python):
A,B = map(int,input().split())

for i in range(1,1001):
    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 n in range(1500):
    if A == n * 8 // 100 and B == n * 10 // 100:
        print(n)
        break
else:
    print(-1)

Solution (Python):
A,B=map(int,input().split())
ans=-1
for i in range(1500):
    if int(i*0.08)==A and int(i*0.1)==B:
        ans=i
        break
print(ans)

Solution (Python):
import math
a,b=map(int,input().split())
for i in range(1,1001):
    if math.floor(i*0.08)==a and math.floor(i*0.1)==b:
        print(i)
        exit()
print(-1)

Solution (Python):
a, b = map(int, input().split())
ans = -1
for i in range(100000):
        if i//12.5==a and i//10==b:
                ans = i
                break
print(ans)

Solution (Python):

import sys, math, itertools, collections, bisect
input = lambda: sys.stdin.buffer.readline().rstrip().decode('utf-8')
inf = float('inf') ;mod = 10**9+7
mans = inf ;ans = 0 ;count = 0 ;pro = 1

a,b = map(int,input().split())
for i in range(2000):
  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(15000):
    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())

for i in range(1, 20000):
    if int(i * 0.08) == a and int(i * 0.1) == b:
        print(i)
        exit()
print(-1)

Solution (Python):
import sys
import math
import bisect

def solve(a, b):
    for i in range(1, 3000):
        c = math.floor(i * 0.08)
        d = math.floor(i * 0.10)
        if c == a and d == b:
            return i
    return -1

def main():
    a, b = map(int, input().split())
    ans = solve(a, b)
    print(ans)

if __name__ == "__main__":
    main()

Solution (Python):
a, b = map(int, input().split())

ans = -1
for i in range(b, 100000):
	if i*8//100 == a and i*10//100 == b:
		ans = i
		break

print(ans)

Solution (Python):
A, B = map(int, input().split())

for i in range(10 ** 6):
    if i * 8 // 100 == A and i * 10 // 100 == 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)
        exit()
print(-1)

Solution (Python):
A,B = list(map(int,input().split()))

for n in range(10000):
  if int(0.08*n)==A and int(0.10*n)==B:
    print(n)
    exit()

print(-1)

Solution (Python):
def main():
    A, B = map(int, input().split())
    for i in range(1, 2000):
        tmp_A = int(i * 0.08)
        tmp_B = int(i * 0.10)
        if tmp_A == A and tmp_B == B:
            print(i)
            exit()

    print(-1)



if __name__ == "__main__":
    main()

Solution (Python):


import sys
sys.setrecursionlimit(300000)


def solve(A: int, B: int):
    ret = -1
    for i in range(0, 10000):
        if int(i * 0.08) == A and int(i * 0.1) == B:
            ret = i
            break
    print(ret)
    return

def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    A = int(next(tokens))  
    B = int(next(tokens))  
    solve(A, B)

if __name__ == '__main__':
    main()

Solution (Python):
a,b=map(int,input().split())
for i in range(1,2000):
  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 p in range(2000):
    if int(p * 0.08) == A and int(p * 0.1) == B:
        print(p)
        break
else:
    print(-1)

Solution (Python):
def main():
    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)
            return
    print(-1)


main()

Solution (Python):

import sys


def solve(A: int, B: int):
    for num in range(1,2000):
        if int(num*0.08) == A and int(num*0.1)==B:
            print(num)
            return
    else:
        print(-1)
    return


def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    A = int(next(tokens))  
    B = int(next(tokens))  
    solve(A, B)

if __name__ == '__main__':
    main()

Solution (Python):
a, b = map(int, raw_input().strip().split())
for x in xrange(10000):
    c1 = int(x * 0.08)
    c2 = int(x * 0.10)

    if c1 == a and c2 == b:
        print x
        exit()

print -1

Solution (Python):
import copy

import math
import fractions

def j(n):
    if n:print("Yes")
    else:print("No")
    exit(0)
rem = 10 ** 9 + 7

"""
def ct(x,y):
    if (x>y):print("+")
    elif (x<y): print("-")
    else: print("?")
"""

def ip():
    return int(input())
def iprow():
    return [int(i) for i in input().split()]
def ips():
    return (int(i) for i in input().split())
def ipmultiplerow(n):
    a = []
    for i in range(n):
        a.append(ip())
    return a
def printrow(a):
    for i in a:
        print(i)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

a,b = ips()

for i in range(1001):
    if int(i*0.08) == a and int(i*0.1) == b:
        print(i)
        exit(0)
print(-1)

Solution (Python):
import math
a,b = list(map(int,input().split()))
for i in range(1,1001):
  if math.floor(i*0.08) == a and math.floor(i*0.1) == b:
    print(i)
    break
else:
  print(-1)

Solution (Python):
a,b=map(int,input().split())
for i in range(10001):
    if int(i*0.08)==a and int(i*0.1)==b:
        print(i)
        exit()
print(-1)

Solution (Python):
import sys
from math import floor
a, b = [int(i) for i in sys.stdin.readline().split()]
flg = False
ans = 0
for i in range(10000):
    if floor(i * 1.08) - i == a and floor(i * 1.1) - i == b:
        flg = True
        ans = i
        break
if flg:
    print(ans)
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())

for n in range(1, 100001):
    if (int(n * 0.08) == A) and (int(n * 0.10) == B):
        print(n)
        break
else:
    print(-1)

Solution (Python):
a,b=map(int,input().split())
for i in range(10**5):
    if (i*2)//25==a and i//10==b:
        print(i)
        break
else:
    print(-1)

Solution (Python):
A, B = map(int, input().split())
for i in range(10**5):
    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(20000):
    if( a== int(i*0.08)):
        if( b == int(i*0.1)):
            print(i)
            exit()

print(-1)

Solution (Python):
a,b = map(int,input().split())
for i in range(10100):
    eight = (i*1.08)//1 - i
    ten = (i*1.1)//1 - i
    if eight==a and ten==b:
        print(i)
        exit()
print(-1)

Solution (Python):
import math
a,b = map(int,input().split())
ans = -1
for i in range(1,10001):
  if math.floor(i*0.08) == a and math.floor(i*0.1) == b:
    ans = i
    break
print(ans)

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

Solution (Python):



def main():
    import sys
    input = sys.stdin.readline
    sys.setrecursionlimit(10**6)
    

    def dump(*args):
        sys.stderr.write(str(args))

    a, b = map(int, input().split())
    from math import floor

    for i in range(2000):
        if floor(i * 0.08) == a and floor(i * 0.1) == b:
            print(i)
            exit(0)
    print(-1)


if __name__ == '__main__':
    main()

Solution (Python):
a,b=map(int,input().split())
ans=-1
for x in range(1,1001):
    if int(x*0.08)==a and int(x*0.10)==b:
        ans=x
        break
print(ans)

Solution (Python):
a, b = map(int, input().split())

for x in range(1, 20000):
    hachi = x * 8 // 100
    juu = x * 10 // 100
    if (a,b) == (hachi, juu):
        print(x)
        exit()
print(-1)

Solution (Python):
from math import floor
A, B = map(int,input().split())
for k in range(1,20000):
    if floor(k*0.08) == A and floor(k*0.1) == B:
        print(k)
        exit(0)
print(-1)

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

Solution (Python):
import math

def makelist(n, m):
    return [[0 for _ in range(m)] for _ in range(n)]





A, B = list(map(int, input().split()))
ans = -1
for n in range(1, 50000):
    if math.floor(n * 0.08) == A and math.floor(n * 0.1) == B:
        ans = n
        break
print(ans)

Solution (Python):
a,b = (int(num) for num in input().split())
ans = -1
for i in range(1,1000000):
    if int(i * 0.08) == a and int(i * 0.1) == b and ans == -1:
        ans = i
        
print(ans)

Solution (Python):

A,B = map(int,input().split())
flag = True
for i in range(10):
    c = 10*B+i
    if int(c*0.08) == A:
        print(c)
        flag = False
        break
    
if flag:
    print(-1)

Solution (Python):
A,B=map(int,input().split())
r=-1
for i in range(1001):
    if i*8//100==A and i*10//100==B:
        r=i
        break
print(r)

Solution (Python):
a,b=map(int,input().split())
x=-1
for i in range(1,1001):
  if int(i*0.08)==a and int(i*0.1)==b:
    x=i
    break
print(x)

Solution (Python):
def main():
    A, B = map(int, input().split())
    for i in range(1, 2000):
        if int(i*0.08) == A and int(i*0.1) == B:
            print(i)
            return
    print(-1)


if __name__ == "__main__":
    main()

Solution (Python):
import sys, bisect, math, itertools, string, queue, copy


from collections import Counter,defaultdict,deque
from itertools import permutations, combinations
from heapq import heappop, heappush

sys.setrecursionlimit(10**8)
mod = 10**9+7
def inp(): return int(input())
def inpm(): return map(int,input().split())
def inpl(): return list(map(int, input().split()))
def inpls(): return list(input().split())
def inplm(n): return list(int(input()) for _ in range(n))
def inplL(n): return [list(input()) for _ in range(n)]
def inplT(n): return [tuple(input()) for _ in range(n)]
def inpll(n): return [list(map(int, input().split())) for _ in range(n)]
def inplls(n): return sorted([list(map(int, input().split())) for _ in range(n)])

def main():
    a,b = inpm()
    for i in range(1,10000):
        if int(i*0.08)==a and int(i*0.1)==b:
            print(i)
            return
    print(-1)
    
if __name__ == "__main__":
    main()

Solution (Python):
a, b = map(int, input().split())
ans = -1
for i in range(0, 1001):
    if 8 * i // 100 == a and i // 10 == b:
        ans = i
        break
print(ans)

Solution (Python):
a,b=map(int,input().split())
for i in range(10**6):
    if int(i*0.08)==a and int(i*0.1)==b:
        print(i)
        exit()
print(-1)

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

Solution (Python):
A, B = map(int, input().split())

for i in range(pow(10, 5)):
    if int(i * 0.08) == A and int(i * 0.10) == B:
        print(i)
        exit()
print(-1)

Solution (Python):
a,b = map(int, input().split())

for x in range(1,2*10**5):
    if int(x*0.08) == a and int(x*0.1) ==b:
        print(x)
        exit()

print(-1)

Solution (Python):

import sys
sys.setrecursionlimit(10**9)
INF=10**18
MOD=10**9+7
def input(): return sys.stdin.readline().rstrip()

def main():
    A,B=map(int,input().split())
    for i in range(1,100000):
        if int(i*0.08)==A and int(i*0.1)==B:
            print(i)
            exit()
    print(-1)

if __name__ == '__main__':
    main()

Solution (Python):
A,B= map(int,input().split())

for i in range(1,10000):
    a = (i * 8) // 100
    b = (i * 10) // 100
    if A == a and B == b:
        print(i)
        exit()
print(-1)

Solution (Python):
A,B = map(int,input().split())

for i in range(10**6):
    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())
for x in range(1000000):
  if int(x * 0.08) == A and int(x * 0.1) == B:
    print(x)
    break
else:
  print(-1)

Solution (Python):
a,b = map(int,input().split())
for i in range(100000):
    if int(i * 0.08) == a and i // 10 == b:
        print(i)
        exit()
print(-1)

Solution (Python):
a,b = map(int,input().split())
cnt = 0
for i in range(1003):
    if int(i *0.08) == a and int(i*0.1) == b:
        print(i)
        cnt = 1
        break
if not cnt :print(-1)

Solution (Python):
import sys
input = sys.stdin.readline
A, B = map(int, input().split())
for x in range(100000):
  if int(x * 0.08) == A and (int(x * 0.10) == B):
    print(x)
    exit(0)
print(-1)

Solution (Python):
A,B=map(int,input().split())
for i in range(1,1100):
    if int(i*0.08)==A and int(i*0.1)==B:
        print(i)
        break
else:
    print(-1)

Solution (Python):
import sys
int1 = lambda x: int(x) - 1
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(500000)

A, B = map(int, read().split())

for i in range(1001):
    a = (i * 0.08) // 1
    b = (i * .1) // 1

    if (a == A) & (b == B):
        print(i)
        sys.exit()

print("-1")

Solution (Python):
from math import floor

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

ans = -1
for i in range(10000):
    e8 = floor(i * 0.08)
    e10 = floor(i * 0.1)

    if e8 == a and e10 == b:
        ans = i
        break

print(ans)

Solution (Python):

A,B = map(int,input().split())

import sys
for i in range(100000):

    if int(i * 0.08) == A and int(i * 0.1) == B:
        print (i)
        sys.exit()

print (-1)

Solution (Python):
def examA():
    S = SI()
    if S=="AAA" or S=="BBB":
        print("No")
    else:
        print("Yes")
    return

def examB():
    N, A, B = LI()
    loop = N//(A+B)
    ans = loop*A + min(A,N%(A+B))
    print(ans)
    return

def examC():
    A, B = LI()
    ans = -1
    for i in range(1,20000):
        if i*8//100==A:
            if i*10//100==B:
                ans = i
                break
    print(ans)
    return

def examD():
    ans = 0
    print(ans)
    return

def examE():
    ans = 0
    print(ans)
    return

def examF():
    ans = 0
    print(ans)
    return

import sys,copy,bisect,itertools,heapq,math,random
from heapq import heappop,heappush,heapify
from collections import Counter,defaultdict,deque
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
def LSI(): return list(map(str,sys.stdin.readline().split()))
def LS(): return sys.stdin.readline().split()
def SI(): return sys.stdin.readline().strip()
global mod,mod2,inf,alphabet,_ep
mod = 10**9 + 7
mod2 = 998244353
inf = 10**18
_ep = 10**(-12)
alphabet = [chr(ord('a') + i) for i in range(26)]

sys.setrecursionlimit(10**6)

if __name__ == '__main__':
    examC()

"""

"""

Solution (Python):
def main():
    A,B = map(int,input().split())
    for i in range(10000):
        if (int(i*0.08) == A) and (int(i*0.1) == B):
            break
    if i == 9999:
        print(-1)
    else:
        print(i)

if __name__ == '__main__':
    main()

Solution (Python):
A,B = map(int,input().split())
for n in range(1,2000):
    a = int(n * 0.08)
    b = int(n * 0.1)
    if a==A and b==B:
        print(n)
        exit()
print(-1)

Solution (Python):
A, B = map(int, input().split())

for i in range(10000):
    a = int(i * 1.08) - i
    b = int(i * 1.10) - i
    if a == A and b == B:
        print(i)
        exit()

print(-1)

Solution (Python):
from collections import Counter,defaultdict,deque
from bisect import bisect_left
import sys,math,itertools,pprint,fractions,time
sys.setrecursionlimit(10**8)
mod = 10**9+7
INF = float('inf')
def inp(): return int(sys.stdin.readline())
def inpl(): return list(map(int, sys.stdin.readline().split()))

a,b = inpl()
res = INF
for i in range(1,10**6):
    if int(i*0.08) == a and int(i*0.1) == b:
        print(i)
        break
else:
    print(-1)

Solution (Python):
from math import floor
A,B = map(int,input().split())

for x in range(2000):
    if floor(x*0.08) == A and floor(x*0.1) == B:
        print(x)
        break
else:
    print(-1)

Solution (Python):
import math

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

for i in range(10101):
    if math.floor(i * 0.08) == a and math.floor(i * 0.1) == b:
        print(i)
        break
else:
    print(-1)

Solution (Python):
a,b = map(int,input().split())

for i in range(1, 10**5):
    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())
ans = -1
for i in range(0,10000):
    a = int(i*0.08)
    b = int(i*0.1)
    if a==A and b==B:
        ans = i
        break
print(ans)

Solution (Python):
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def SI(): return sys.stdin.readline()[:-1]

def main():
    a,b=MI()
    for ans in range(1,2000):
        if ans*2//25==a and ans//10==b:break
    if ans==1999:print(-1)
    else:print(ans)

main()

Solution (Python):
a, b = list(map(int, input().split()))

for i in range(1, 100000):
    tmpa = i * 8 // 100
    tmpb = i * 10 // 100
    if tmpa == a  and tmpb == b:
        print(i)
        exit()
print(-1)

Solution (Python):
A,B = map(int,input().split())

ans = -1
for i in range(10100):
    if (i*8//100 == A) and (i*10//100 == B):
        ans = i
        break
print(ans)

Solution (Python):
A,B = list(map(int,input().split()))
flag=False
for i in range(100001):
    if int(i*0.08)==A and int(i*0.1)==B:
        flag=True
        break

if flag:
    print(i)
else:
    print(-1)

Solution (Python):
a, b = map(int, input().split())

f = False
for x in range(1, 2000):
    if int(x * 0.08) == a and int(x * 0.1) == b:
        if not f:
            print(x)
        f = True

if not f:
    print(-1)

Solution (Python):
A, B = map(int, input().split())

for i in range(1, 100000):
    if int(i * 0.08) == A and int(i * 0.1) == B:
        print(i)
        exit()
print(-1)

Solution (Python):
def main():

    A, B = map(int, input().split())
    for v in range(0, 100000):
        if int(v * 0.08) == A and int(v * 0.1) == B:
            return v
    return -1

if __name__ == '__main__':
    print(main())

Solution (Python):
A, B = map(int, input().split())
for i in range(2000):
    if int(i*0.08) == A and int(i*0.10) == B:
        print(i)
        break
else:
    print(-1)

Solution (Python):
import math
import sys
A,B = map(int,input().split())
i = 0
while math.floor(i*0.08) <= A and math.floor(i*0.10) <= B:
  if math.floor(i*0.08) == A and math.floor(i*0.10) == B:
    print(i)
    sys.exit(0)
  i+=1
print(-1)

Solution (Python):
A, B = list(map(int, input().split()))

for i in range(5000):
  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())
for i in range(1300):
    if int(i * 0.08) == A and int(i * 0.1) == B:
        print(i)
        break
else:
    print('-1')

Solution (Python):











import sys
sys.setrecursionlimit(10**6)
input=sys.stdin.readline
from math import floor,sqrt,factorial,hypot,log 
from heapq import heappop, heappush, heappushpop
from collections import Counter,defaultdict,deque
from itertools import accumulate,permutations,combinations,product,combinations_with_replacement
from bisect import bisect_left,bisect_right
from copy import deepcopy
from fractions import gcd
from random import randint
def ceil(a,b): return (a+b-1)//b
inf=float('inf')
mod = 10**9+7
def pprint(*A): 
    for a in A:     print(*a,sep='\n')
def INT_(n): return int(n)-1
def MI(): return map(int,input().split())
def MF(): return map(float, input().split())
def MI_(): return map(INT_,input().split())
def LI(): return list(MI())
def LI_(): return [int(x) - 1 for x in input().split()]
def LF(): return list(MF())
def LIN(n:int): return [I() for _ in range(n)]
def LLIN(n: int): return [LI() for _ in range(n)]
def LLIN_(n: int): return [LI_() for _ in range(n)]
def LLI(): return [list(map(int, l.split() )) for l in input()]
def I(): return int(input())
def F(): return float(input())
def ST(): return input().replace('\n', '')
def main():
    A,B=MI()
    for i in range(100000):
        if(int(i*0.08)==A and int(i*0.1)==B):
            print(i)
            return
    print(-1)

if __name__ == '__main__':
    main()

Solution (Python):
import math
import sys


(A,B) = list(map(int,input().split()))

for x in range(1,1011):
    a = x * 8 //100
    b = x * 10 // 100
    if a == A and b ==B: 
        print(x)
        exit(0)

print(-1)

Solution (Python):

import sys
input = sys.stdin.readline

a, b = [int(item) for item in input().split()]
for i in range(20000):
    eight = int(i * 0.08)
    ten = int(i * 0.1)
    if eight == a and ten == b:
        print(i)
        exit()
print(-1)

Solution (Python):
a,b=map(int,input().split())
ans=-1
for i in range(1500):
    if int(i*0.08) == a and int(i*0.10)==b:
        ans=i
        break
print(ans)

Solution (Python):
def main():
    A,B=map(int, input().split())
    for i in range(1,100000):
        if int(i*.08)==A and int(i*.1)==B:
            print(i)
            break
    else:
        print(-1)

if __name__ == "__main__":
    main()

Solution (Python):
A, B = map(int, input().split())


ans = -1
for x in range(100000):
    a = int(x * 0.08)
    b = int(x * 0.1)
    if a == A and b == B:
        ans = x
        break

print(ans)

Solution (Python):
a, b = map(int, input().split())
for i in range(10001):
  if a <= i*0.08 < a+1 and b <= i*0.1 < b+1:
    print(i)
    break
else:
  print(-1)

Solution (Python):
A, B = map(int, input().split())
for i in range(1, 10**5):
    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(10000):
  if int(i*0.08) == a and int(i*0.1) == b:
    print(i)
    break
else:
  print(-1)

Solution (Python):
def main():
    A, B = map(int, input().split())

    for x in range(10000):
        if int(x * 0.08) == A and int(x * 0.1) == B:
            print(x)
            return

    print(-1)


if __name__ == '__main__':
    main()

Solution (Python):
A, B = map(int, input().split())
for i in range(1,100000):
  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())

for i in range(1, 100000):
    x = i*8//100
    y = i*10//100
    if x == a and y == b:
        print(i)
        exit()
print(-1)

Solution (Python):
def solve():
    N, M = map(int, input().split())
    c = -1
    for i in range(1, 1001):
        a = int(i * 0.08)
        b = int(i * 0.1)
        if a == N and b == M:
            c = i
            break

    return c

print(solve())

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

    if taxa == a and taxb == b:
        ans = i
        break

print(ans)

Solution (Python):
a, b = [int(i) for i in input().split()]

for i in range(10000):
    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())
for x in range(10000):
    if x * 8 // 100 == a and x * 10 // 100 == b:
        print(x)
        exit(0)
print(-1)

Solution (Python):
A, B = map(int, raw_input().split())

for i in range(10000):
  if i*8/100==A and i*10/100==B:
    print i
    exit(0)
print -1

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

Solution (Python):
A, B = map(int, input().split())
for i in range(10**4):
  if int(i*0.08) == A and int(i*0.1) == B:
    print(i)
    break
else:
  print(-1)

Solution (Python):
def main():
    A, B = list(map(int, input().split()))
    for i in range(1010):
        if int(i * 0.08) == A and int(i * 0.1) == B:
            return i
    return -1
   

print(main())

Solution (Python):
a,b=map(int,input().split())
for n in range(10**6):
  if (n*8)//100==a and (n//10)==b:print(n);exit()
print(-1)

Solution (Python):
import os
import sys

if os.getenv("LOCAL"):
    sys.stdin = open("_in.txt", "r")

sys.setrecursionlimit(10 ** 9)
INF = float("inf")
IINF = 10 ** 18
MOD = 10 ** 9 + 7


A, B = list(map(int, sys.stdin.buffer.readline().split()))

for n in range(100000):
    if int(n * 0.08) == A and int (n * 0.10) == B:
        print(n)
        exit()
print(-1)

Solution (Python):
rr = raw_input
rri = lambda: int(rr())
rrm = lambda: map(int, rr().split())

def solve(A, B):
    for price in xrange(1, 1000000):
        tax1 =int(price * 0.08)
        tax2 = int(price* 0.10)
        if tax1 == A and tax2==B:
            return price
    return -1


print solve(*rrm())

Solution (Python):
a, b = map(int, input().split())
for i in range(20000):
    if int(i * 0.08) == a and int(i * 0.1) == b:
        print(i)
        exit()
print(-1)

Solution (Python):
from math import floor

a, b = map(int, input().split())
for i in range(1, 1000000):
    if floor(i * 0.08) == a and floor(i * 0.1) == b:
        print(i)
        exit()
print(-1)

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

Solution (Python):

from collections import defaultdict,deque
from heapq import heappush, heappop
from itertools import permutations
import sys
import math
import bisect
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def I(): return int(sys.stdin.readline())
def LS():return [list(x) for x in sys.stdin.readline().split()]
def S():
    res = list(sys.stdin.readline())
    if res[-1] == "\n":
        return res[:-1]
    return res
def IR(n):
    return [I() for i in range(n)]
def LIR(n):
    return [LI() for i in range(n)]
def SR(n):
    return [S() for i in range(n)]
def LSR(n):
    return [LS() for i in range(n)]

sys.setrecursionlimit(1000000)
mod = 1000000007

def solve():
    a,b = LI()
    for i in range(1000000):
        if int(i*0.08) == a and int(i*0.10) == b:
            print(i)
            return
    print(-1)
    return


if __name__ == "__main__":
    solve()

Solution (Python):
printn = lambda x: print(x,end='')
inn = lambda : int(input())
inl   = lambda: list(map(int, input().split()))
inm   = lambda:      map(int, input().split())
ins = lambda : input().strip()
DBG = True 
BIG = 10**18
R = 10**9 + 7

def ddprint(x):
  if DBG:
    print(x)

a,b = inm()
for i in range(1,11000):
    if (i*8)//100==a and (i*10)//100==b:
        print(i)
        exit()
print(-1)

Solution (Python):
import sys
import math
from collections import defaultdict

sys.setrecursionlimit(10**7)
def input():
    return sys.stdin.readline()[:-1]

mod = 10**9 + 7

def I(): return int(input())
def LI(): return list(map(int, input().split()))
def LIR(row,col):
    if row <= 0:
        return [[] for _ in range(col)]
    elif col == 1:
        return [I() for _ in range(row)]
    else:
        read_all = [LI() for _ in range(row)]
        return map(list, zip(*read_all))



A,B = LI()

for i in range(1,1010):
    if math.floor(i*0.08)==A and math.floor(i*0.1)==B:
        print(i)
        exit()
print(-1)

Solution (Python):
from collections import *
from itertools import *
from bisect import *
from heapq import *
import copy
import math
from fractions import gcd

mod=10**9+7

A,B=map(int,input().split())


for i in range(1,500001):
    
    if (i*8)//100==A and (i*10)//100==B:
        print(i)
        exit()

print(-1)

Solution (Python):
import sys

stdin = sys.stdin

ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline().rstrip()  

a, b = na()
for i in range(1, 100000):
    if i*8//100 == a and i*10//100 == b:
        print(i)
        sys.exit(0)
print(-1)

Solution (Python):
import sys

a, b = [int(w) for w in input().split()]

max_n = (b + 1) * 10

for i in range(max_n):
    if a == int(i * 0.08) and b == int(i * 0.1):
        print(i)
        sys.exit()

print(-1)

Solution (Python):
a, b = list(map(int, input().split()))
for i in range(10000):
    if i * 8 // 100 == a and i * 10 // 100 == b:
        print(i)
        break
else:
    print(-1)

Solution (Python):
A,B = map(int, input().split())

ans = 0
while ans < 1000*A:
    if int(ans*0.08) == A and int(ans*0.1) == B:
        break
    ans += 1

if ans == 1000*A:
    ans = -1
print(ans)

Solution (Python):


A,B=map(int,input().split())

for i in range(1,200000):
    if (i*0.08)//1==A and (i*0.1)//1==B:
        print(i)
        exit()

print(-1)

Solution (Python):
a,b=map(int,input().split())
for i in range(1,10**5*2):
	if int(i*0.08+10**-12)==a:
		if int(i*0.1+10**-12)==b:
			print(i)
			exit()
print(-1)