#include <bits/stdc++.h>

int solve();

int main()
{
	int ans{solve()};
	if (ans < 0) puts("Impossible");
	else printf("%d\n", ans);

	return 0;
}

int solve()
{
	int A, B, C;
	scanf("%d%d%d", &A, &B, &C);
	
	for (int cost{1}; cost <= A + 10 * B; cost++)
	{
		for (int a_i{}; a_i <= A; a_i++)
		{
			for (int b_i{}; b_i <= B; b_i++)
			{
				if (a_i + 10 * b_i < cost) continue;
				int change{a_i + 10 * b_i - cost};
				if (A - a_i + B - b_i + change / 10 + change % 10 == C)
					return cost;
			}
		}
	}
	return -1;
}