#include <bits/stdc++.h>
using namespace std;

int change(int a, int b, int p){
    int ch = (a + 10 * b - p);
    return (ch / 10) + (ch % 10);
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int A,B,C;
    cin >> A >> B >> C;
    int min_p = 1000;
    for (int a = 0; a <= A; ++a){
        for (int b = 0; b <= B; ++b){
            for (int p = 1; p <= a + 10*b; ++p){
                if (a == 0 and b == 0) continue;
                if (A - a + B - b + change(a, b, p) == C){
                    min_p = min(min_p, p);
                }
            }
        }
    }
    if (min_p == 1000){
        cout << "Impossible" << endl;
    }else{
        cout << min_p << endl;
    }
    return 0;
}