using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        for (var i = 1; i <= c[0] + c[1] * 10; ++i)
        {
            for (var a = 0; a <= c[0]; ++a) for (var b = 0; b <= c[1]; ++b)
            {
                if (i <= a + b * 10)
                {
                    var res = a + b * 10 - i;
                    if (c[0] - a + c[1] - b + res / 10 + res % 10 == c[2])
                    {
                        WriteLine(i);
                        return;
                    }
                }
            }
        }
        WriteLine("Impossible");
    }
}