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

use = (A + B) -C

if use > A:
    if B != 0:
        print(A + ((use-A)*10))
    else:
       print("Impossible") 
elif use <= 0:
    print("Impossible")
else:
    if len(str(use)) == 1:
        print(use)
    else:
        if use + 1 <= A:
            print(use -9)
        else:
            print(use)