x, y, z = map(int, input().split())
sum = x + 10 * y
y_10, x_10 = divmod(sum, 10)
if x == z and y ==0:
    print('Impossible')
    exit()
if y == 0:
    if x < z:
        print('Impossible')
        exit()
elif x + y + 10 < z:
    print('Impossible')
    exit()
if y_10>z:
    print((y-z) * 10 + x)
if x_10+y_10-z>=0:
    if x_10>x_10+y_10-z:
        print(x_10+y_10-z)
        exit()
else:
    change_count = (z-y_10)//9
    if change_count == 0:
        change_count = 1
    print(y_10 - change_count + x_10 + change_count*10-z)