using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using static System.Console;
using Pair = System.Collections.Generic.KeyValuePair<int, int>;
//using System.Numerics;
//using static System.Math;

class Program
{
    static void Main()
    {
        //SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
        new Program().solve();
        Out.Flush();
    }
    Scanner cin = new Scanner();
    readonly int[] dd = { 0, 1, 0, -1, 0 };
    readonly int mod = 1000000007;
    readonly string alfa = "abcdefghijklmnopqrstuvwxyz";
    readonly string ALFA = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    int N;
    int R, C;
    List<Edge>[] G;
    long[] W;
    const long inf = long.MaxValue / 3;
    bool[] B;
    bool ok = true;
    void solve()
    {
        R = cin.nextint;
        C = cin.nextint;
        N = cin.nextint;
        G = Enumerable.Range(0, R + C).Select(i => new List<Edge>()).ToArray();
        for (int i = 0; i < N; i++)
        {
            int r = cin.nextint - 1;
            int c = cin.nextint - 1;
            int a = cin.nextint;
            G[r].Add(new Edge(R + c, a));
            G[R + c].Add(new Edge(r, a));
        }
        W = Enumerable.Repeat(inf, R + C).ToArray();
        B = new bool[R + C];
        for (int i = 0; i < R + C; i++)
        {
            if (B[i]) continue;
            xmin = ymin = inf;
            dfs(i, 0);
            if(xmin + ymin < 0)
            {
                ok = false;
                break;
            }
        }
        //WriteLine(string.Join(" ", W));
        if (ok)
        {
            WriteLine("Yes");
        }
        else
        {
            WriteLine("No");
        }
    }
    long xmin, ymin;
    void dfs(int u, long value)
    {
        if (u < R)
        {
            xmin = Math.Min(xmin, value);
        }
        else
        {
            ymin = Math.Min(ymin, value);
        }
        //WriteLine(u + 1);
        if (B[u])
        {
            if (W[u] != value)
            {
                ok = false;
            }
            return;
        }
        B[u] = true;
        W[u] = value;
        foreach (var v in G[u])
        {
            dfs(v.to, v.cost - value);
        }
    }


    struct Edge : IComparable<Edge>
    {
        public int to; public long cost;
        public Edge(int to, long cost)
        {
            this.to = to;
            this.cost = cost;
        }
        public int CompareTo(Edge e)
        {
            return cost.CompareTo(e.cost);
        }
    }

}

class Scanner
{
    string[] s; int i;
    char[] cs = new char[] { ' ' };
    public Scanner() { s = new string[0]; i = 0; }
    public string[] scan { get { return ReadLine().Split(); } }
    public int[] scanint { get { return Array.ConvertAll(scan, int.Parse); } }
    public long[] scanlong { get { return Array.ConvertAll(scan, long.Parse); } }
    public double[] scandouble { get { return Array.ConvertAll(scan, double.Parse); } }
    public string next
    {
        get
        {
            if (i < s.Length) return s[i++];
            string st = ReadLine();
            while (st == "") st = ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            i = 0;
            return next;
        }
    }
    public int nextint { get { return int.Parse(next); } }
    public long nextlong { get { return long.Parse(next); } }
    public double nextdouble { get { return double.Parse(next); } }
}

Measured memory_bytes: 56588