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")