import sys

a, b,c = map(int, input().split())
j = 0

if b == 0:
  j = 0
else:
  j = b + 8

if a+j <= c:
  print("Impossible")
  sys.exit()

if b - c > 0:
  print(a + 10 * (b - c))

if b == c:
  print(a)

if b - c < 0 :
  if a < c -b:
    print(a + b - c + 9)
  elif a > c - b:
    if a - (c - b) < 10:
      print(a - ( c - b ))
    else:
      print(a + b - c - 9)
  elif a == c - b:
    print(a)