import sys

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

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