#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstring>
#include <assert.h>
#include <sys/time.h>
#include <fstream>

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)  FOR(i,0,n)
#define REP(i,n)  FOR(i,0,n)
#define each(i,c) for(auto i=(c).begin(); i!=(c).end(); ++i)
#define EACH(i,c) for(auto i=(c).begin(); i!=(c).end(); ++i)
#define exist(s,e) ((s).find(e)!=(s).end())

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#define deb(x) cerr << #x << " = " << (x) << " , ";
#define debl cerr << " (L" << __LINE__ << ")"<< endl;
#define sz(s) (int)((s).size())


#define clr(a) memset((a),0,sizeof(a))
#define nclr(a) memset((a),-1,sizeof(a))
#define pb push_back
#define INRANGE(x,s,e) ((s)<=(x) && (x)<(e))
#define MP(x,y) make_pair((x),(y))

double pi=3.14159265358979323846;

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<string> vs;

template<typename T> std::ostream& operator<<(std::ostream& os, const vector<T>& z){
	os << "[ ";
	REP(i,z.size())os << z[i] << ", " ;
	return ( os << "]" << endl);
}

template<typename T> std::ostream& operator<<(std::ostream& os, const set<T>& z){
	os << "set( ";
	EACH(p,z)os << (*p) << ", " ;
	return ( os << ")" << endl);
}

template<typename T,typename U> std::ostream& operator<<(std::ostream& os, const map<T,U>& z){
	os << "{ ";
	EACH(p,z)os << (p->first) << ": " << (p->second) << ", " ;
	return ( os << "}" << endl);
}

template<typename T,typename U> std::ostream& operator<<(std::ostream& os, const pair<T,U>& z){
	return ( os << "(" << z.first << ", " << z.second << ",)" );
}

double get_time(){
	struct timeval tv;
	gettimeofday(&tv, NULL);
	return tv.tv_sec + tv.tv_usec*1e-6;
}

typedef unsigned int uint32_t;
struct RND{
	uint32_t x;
	uint32_t y;
	uint32_t z;
	uint32_t w;
	RND(){
		x=123456789;
		y=362436069;
		z=521288629;
		w=88675123;
	}
	void init(int seed){
		x=123456789;
		y=362436069;
		z=521288629;
		w=seed+100;
		REP(i,10)get();
	}
	uint32_t get(){
		uint32_t t;
		t=x^(x<<11);
		x=y;y=z;z=w;
		w=(w^(w>>19))^(t^(t>>8));
		return w;
	}
};
RND rnd;

typedef pair<ll,ll> pll;
ll R,C,N;
vector<vector<pll>> edge;
vl visit;
vl num;
bool pos = true;
ll min_1;
ll min_2;

void rec(int i, ll val){
	//deb(i);deb(val);debl;
	if(visit[i]){
		if(val!=num[i])pos = false;
		return;
	}
	visit[i]=1;
	num[i]=val;
	if(i<R) min_1 = min(min_1, val);
	else min_2 = min(min_2, val);

	rep(ind, edge[i].size()){
		int i2 = edge[i][ind].first;
		ll a = edge[i][ind].second;
		ll val2 = a - val;
		rec(i2, val2);
	}
}

void _main(istream &inp){
	inp >>R>>C>>N;
	//deb(R);deb(C);deb(N);debl;
	edge.resize(R+C);
	visit.resize(R+C);
	num.resize(R+C);

	rep(i,N){
		ll r,c,a;
		inp >>r >> c >> a;
		r-=1;
		c-=1;
		int i1 = r;
		int i2 = R+c;
		edge[i1].emplace_back(i2, a);
		edge[i2].emplace_back(i1, a);
	}
	//deb(edge);debl;

	rep(id,num.size()){
		if(visit[id]==0){
			min_1 = 1e16;
			min_2 = 1e16;
			rec(id, 0);
			if(min_1+min_2<0)pos = false;
		}
	}
	if(pos){
		cout <<"Yes" << endl;
	}
	else{
		cout << "No" << endl;
	}
}

int main(){
	if(0){
		ifstream ifs("test.txt");
		_main(ifs);
	}
	else{
		_main(cin);
	}
	return 0;
}


Measured memory_bytes: 16384