# coding: UTF-8
import sys
#sys.setrecursionlimit(n)
import heapq
import re
import bisect
import random
import math
import itertools
from collections import defaultdict, deque
from copy import deepcopy
from decimal import *

a, b, c = map(int, input().split())
ans = []
def dfs(x, y, pay):
    if x + y == c:
        ans.append(pay)
    if x + y < c:
        return -1
    if y > 0:
        dfs(x, y - 1, pay + 10)
    if x >= 10:
        dfs(x - 10, y + 1, pay)
    if x > 0:
        dfs(x - 1, y, pay + 1)
    return -1

if a + b == c:
    print('Impossible')
else:
    dfs(a, b, 0)
    if ans:
        print(min(ans))
    else:
        print('Impossible')