A, B, C = map(int, input().split())
n = A + B - C 
if n > 0:
    if n < 10 and n <= A:
        print(n)
    elif n < 10 and n > A:
        print(A+10*(n-A))
    elif n >= 10 :
        n1 = n + n//10 
        if n1 <= A:
            print(n1 - n1//10*10)
        else:
            print(A + (n-A)*10)                    
elif n < 0 and n > -9:
    print(10 + n -1)    
else:
    print("Impossible")