#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
    int a, b, c; cin>>a>>b>>c;
    for(int r=0; r<=9; r++){
        if(c>=r && a+10*b>r+10*(c-r)){
            cout<<a+10*b-r-10*(c-r)<<endl;
            return 0;
        }
    }
    cout<<"Impossible"<<endl;
    return 0;
}