import sys
X,Y = map(int,input().split())
Z = (Y*100//X)
s,e = 0,100000000000
ans = e
# if X == Y:
# print(-1)
# sys.exit()
while s<=e:
mid = (s+e)//2
Z2 = ((Y+mid)*100//(X+mid))
# print(s,e,Z,Z2)
if Z2 > Z:
if ans > mid:
ans = mid
e = mid-1
else:
s = mid+1
if ans == 100000000000:
print(-1)
else:
print(ans)