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

def get_price(i: int) ->int:
  price = (10 * b + a) - (10 * (c-i) + i) 
  return price

# index= = 購入後のaの値 となる 買った商品の購入額のリスト
plist=[0]*(c+1)

if a+b < c:
  pind=0
  for i in range(c+1):
    plist[i]=get_price(i)
    if plist[i] <= 0:
      pind=i
  if plist[pind] <= 0 and pind < c:
    pind+=1
#途中で正に変わる場合の仕掛け
#チェックが必要
#変化後のa=pind 変化後のb=c-pind
  price=plist[pind]
  
  checka=a
  checkb=b
  defb=b-(c-pind)
  checkb=c-pind
  temp=10 * defb - price
  checka+=temp%10
  if b != 0:
    checkb+=temp//b

  if max(plist) <= 0:
    print("Impossible")
  elif (checka == pind and checkb == c-pind):
    print(price)
  else:
    print("Impossible")

else:
  pind=0
  for i in range(c+1):
    plist[i]=get_price(i)
    if plist[i] <= 0:
      pind=i
  if plist[pind] <= 0 and pind < c:
    pind+=1  
  price=plist[pind]
    
  if price <= 0 :
    print("Impossible")
  else:
    print(price)