from sys import stdin

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

    num = A + (B * 10)
    for i in range(num + 1):
        n1, n10 = divmod(num - i, 10)
        if n1 + n10 == C:
            print(i)
            break
    else:
        print('Impossible')

input = lambda: stdin.readline()
main()