public static string organizingContainers(List<List<int>> container)
    {
        int n = container.Count;
        List<long> containerCapacity = new List<long>();
        List<long> ballByTypeCount = new List<long>();
        for (int i = 0; i < n; i++) {
            containerCapacity.Add(0);
            ballByTypeCount.Add(0);
        }
        for (int i = 0; i < n; i++){
            for (int j = 0; j < n; j++){
                containerCapacity[i] += container[i][j];
                ballByTypeCount[j] += container[i][j];                
            }
        }
        containerCapacity.Sort();
        ballByTypeCount.Sort();
        for (int i = 0; i < n; i++){
            if (containerCapacity[i] != ballByTypeCount[i])
                return "Impossible";
        }
        return "Possible";
    }