x, y = map(int, input().split())
z = (y*100) // x

if z >= 99:
  print(-1)

else:
  answer = 0
  left = 1
  right = x

  while left <= right:
    mid = (left + right) // 2
    if(y+mid) * 100 // (x+mid) <= z:
      left = mid + 1
    else:
      answer = mid
      right = mid -1

print(answer)

#https://hillier.tistory.com/70 참고했습니다.
