A, B, C = map(int, input().split())

# 複数回の会計に分割できる
def calc(a,b,coins):
  if a + b is coins:
    return 0
  elif a + b - coins <= -9:
    return None
  elif a + b < coins:
    return None if b is 0 else 1 + calc(a+9, b-1, coins) # 1Gの商品を10G払って購入
  else:
    if a >= 11 and a+b-coins >= 10:
      return 1 + calc(a-11, b+1, coins) # 1Gの商品を11G払って購入
    return 1 + calc(a-1, b, coins) if a >= 1 else 10 + calc(a, b-1, coins)
      
print(calc(A, B, C) or "Impossible")