#include <iostream>

constexpr int X = 300;

void solve() {
    int a, b, c;
    std::cin >> a >> b >> c;

    for (int d = 1; d <= X; ++d) {
        for (int i = 0; i <= a; ++i) {
            for (int j = 0; j <= b; ++j) {
                int m = i + j * 10;
                if (m < d) continue;

                m -= d;
                if ((a - i) + (b - j) + m / 10 + m % 10 == c) {
                    std::cout << d << std::endl;
                    return;
                }
            }
        }
    }

    std::cout << "Impossible" << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}