INF = 10 ** 9
import sys
sys.setrecursionlimit(100000000)
dy = (-1,0,1,0)
dx = (0,1,0,-1)
from  collections import deque

def main():
    a,b,c = map(int,input().split())
    if c - b <= 0:
        ans = a + 10 * (b - c)
    else:
        c -= b
        if a >= 10 * c:
            ans = a - 10 * c
        elif a < c:
            ans = 'Imossible'
        else:
            s = a//10
            flag = False
            while s > -1:
                if a - 10 * s - (c - s) > 1:
                    ans = a - 10 * s - (c - s)
                    flag = True
                    break
                s -= 1
            if flag == False:
                ans = 'Impossible'
    
    print(ans)
if __name__ == '__main__':
    main()