using System;

using System.Collections.Generic;

using System.Text;

using System.Linq;

public class Program

{

    public static void Main()

    {

        string input = @"

                        20

            _ , _, _, _|23

            _ , 2, _, _|24

            _ , _, 4, _|25

            _ , _, 4, _|27

            --------------

            12,23,30,25,12";

        Console.WriteLine(FindSolution(new ProblemDefinition(input)).DumpCells());

    }

    private static ProblemDefinition FindSolution(ProblemDefinition prob)

    {

        Ranges ranges = prob.ToRanges();

        bool madeChange = true;

        while(!madeChange)

        {

            for(int y = 0; y < 4; y++)

            {

                madeChange |= ranges.ImproveRow(y, prob.HorizSums[y]);

            }

            for(int x = 0; x < 4; x++)

            {

                madeChange |= ranges.ImproveColumn(x, prob.VerticalSums[x]);

            }

            madeChange |= ranges.ImproveDiagNorthEast(prob.DiagNorthEastSum);

            madeChange |= ranges.ImproveDiagSouthEast(prob.DiagSouthEastSum);

        }

        return prob;

    }

}

​

public class ProblemDefinition

{

    private int?[,] m_Cells = new int?[4,4];

    public int[] VerticalSums = new int[4];

    public int[] HorizSums = new int[4];

    public int DiagNorthEastSum;

    public int DiagSouthEastSum;

    public ProblemDefinition(string input)

    {

        string[] lines = input.Split('\n').Where(s => !string.IsNullOrWhiteSpace(s)).ToArray();

        DiagNorthEastSum = int.Parse(lines[0]);

        for(int y = 0; y < 4; y++)

        {

            string line = lines[y+1];

            string[] parts = line.Split('|');

            HorizSums[y] = int.Parse(parts[1]);

            string[] cells = parts[0].Split(',').Select(s => s.Trim()).ToArray();

            for(int x = 0; x < 4; x++)

            {

                if(cells[x] == "_") continue;   

                m_Cells[x,y] = int.Parse(cells[x]);

            }

        }

        string lastLine = lines[6];

        VerticalSums = lastLine.Split(',').Select(s => int.Parse(s)).ToArray();

        DiagSouthEastSum = VerticalSums.Last();

        VerticalSums = VerticalSums.Take(4).ToArray();

    }

    public string DumpCells()

    {

        StringBuilder sb = new StringBuilder();

        for(int y = 0; y < m_Cells.GetLength(1); y++)

        {

            for(int x = 0; x < m_Cells.GetLength(0); x++)

            {

                sb.Append(m_Cells[x,y]?.ToString() ?? "_");

                sb.Append(',');

            }

            sb.Remove(sb.Length - 1, 1);

            sb.Append('\n');

        }   

        sb.Remove(sb.Length - 1, 1);

        return sb.ToString();

    }

    public Ranges ToRanges()

    {

        Ranges ranges = new Ranges();

        for(int y = 0; y < m_Cells.GetLength(1); y++)

        {

            for(int x = 0; x < m_Cells.GetLength(0); x++)

            {

                if(m_Cells[x,y].HasValue)

                {

                    ranges.SetSingleValue(x,y,m_Cells[x,y].Value);

                }

            }

        }   

        return ranges;

    }

}

​

public class Ranges

{

    private int[,] m_Mins = new int[4,4];

    private int[,] m_Maxes = new int[4,4];

    public Ranges()

    {

        for(int x = 0; x < m_Mins.GetLength(0); x++)

        {

            for(int y = 0; y < m_Mins.GetLength(1); y++)

            {

                m_Mins[x,y] = 1;

                m_Maxes[x,y] = 9;

            }

        }       

    }

    public void SetSingleValue(int x, int y, int value)

    {

        m_Mins[x,y] = m_Mins[x,y] = value;

    }

    public void ImproveMin(int x, int y, int value)

    {

        m_Mins[x,y] = Math.Max(m_Mins[x,y], value);

    }

    public void ImproveMax(int x, int y, int value)

    {

        m_Maxes[x,y] = Math.Min(m_Maxes[x,y], value);

    }

    public bool ImproveRow(int y, int sum)

    ^   {

        }

}