// yukicoder: No.825 賢いお買い物
// 2019.6.23 bal4u

#include <stdio.h>

int main()
{
	int a, b, c, ans;
	
	scanf("%d%d%d", &a, &b, &c);
	ans = -1;
	if (a + b == c) {
		if (b > 0) ans = 9;
	} else if (a + b > c) {
		if (b < c) ans = (a + b - c) % 9;
		else ans = a + 10*(b - c);
	} else if (b > 0 && a + b - 1 + 9 >= c) ans = 10 - (c - (a + b - 1));
	if (ans < 0) puts("Impossible");
	else printf("%d\n", ans);
	return 0;
}