a,b,c=map(int, input().split())
if(b==0):
    if(a<=c):
        print("Impossible")
    else:
        print(a-c)
else:
    if(a+b+10<=c):
        print("Impossible")
    elif(a+b<=c<=a+b+9):
        print(9-(c-a-b))
    elif(a+b-c<=a<=9):
        print(a)
    elif(a+b-c<=a-a//10):
        print((a+b-c)%9)
    else:
        print(a+(b-c)*10)