#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 <deque>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
#include <cctype>
#include <cstring>
#include <ctime>
#include <iterator>
#include <bitset>
#include <numeric>
#include <list>
#include <iomanip>
#include <cassert>

#if __cplusplus >= 201103L
#include <array>
#include <tuple>
#include <initializer_list>
#include <unordered_set>
#include <unordered_map>
#include <forward_list>

#define cauto const auto&
#define ALL(v) begin(v),end(v)
#else
#define ALL(v) (v).begin(),(v).end()
#endif

using namespace std;


namespace{
typedef long long LL;
typedef pair<int,int> pii;
typedef pair<LL,LL> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll, vLL;
typedef vector<vector<long long> > vvll, vvLL;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
	v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
	stringstream ss;
	ss << f;
	ss >> t;
}


#define REP(i,n) for(int i=0;i<int(n);++i)
#define RALL(v) (v).rbegin(),(v).rend()


#define MOD 1000000007LL
#define EPS 1e-8

struct union_find{
	typedef unsigned size_type;
	vector<int> par;
	size_type grs;
	explicit union_find(size_type n = 0){ init(n); }
	void init(size_type n){
		par.assign(n, -1);
		grs = n;
	}
	size_type find(size_type x){
		if(par[x] < 0){ return x; }
		return par[x] = find(par[x]);
	}
	size_type size(size_type x){
		return -par[find(x)];
	}
	size_type groups(){
		return grs;
	}
	bool unite(size_type x, size_type y){
		x = find(x);
		y = find(y);
		if(x == y){ return false; }
		if(par[x] < par[y]){ swap(x, y); }
		par[y] += par[x];
		par[x] = y;
		--grs;
		return true;
	}
	bool same(size_type x, size_type y){
		return find(x) == find(y);
	}
};

bool solve(){
	const LL INF = LLONG_MAX / 5;

	int h, w, n;
	scanf("%d%d%d", &h, &w, &n);

	vector<int> ys(n), xs(n), as(n);
	VV(pii) G(h + w);
	union_find uf(h + w);
	for(int i = 0; i < n; ++i){
		scanf("%d%d%d", &ys[i], &xs[i], &as[i]);
		--xs[i];
		--ys[i];
		G[ys[i]].emplace_back(xs[i] + h, as[i]);
		G[xs[i] + h].emplace_back(ys[i], as[i]);
		uf.unite(ys[i], xs[i] + h);
	}

	vector<LL> val(h + w, INF);
	queue<int> q;
	for(int i = 0; i < h + w; ++i){
		if(uf.find(i) == i){
			val[i] = 0;
			q.push(i);
		}
	}
	while(!q.empty()){
		int u = q.front();
		q.pop();
		for(cauto p : G[u]){
			if(val[p.first] == INF){
				val[p.first] = p.second - val[u];
				q.push(p.first);
			}
		}
	}

	for(int i = 0; i < n; ++i){
		if(val[ys[i]] + val[xs[i] + h] != as[i]){ return false; }
	}

	vector<LL> miny(h + w, INF), minx(h + w, INF);
	for(int i = 0; i < h + w; ++i){
		int f = uf.find(i);
		if(i < h){
			miny[f] = min(miny[f], val[i]);
		}
		else{
			minx[f] = min(minx[f], val[i]);
		}
	}
	for(int i = 0; i < h + w; ++i){
		if(uf.find(i) == i){
			if(miny[i] + minx[i] < 0){ return false; }
		}
	}

	return true;
}

void mainmain(){
	puts(solve() ? "Yes" : "No");
}



}
int main() try{
//	ios::sync_with_stdio(false); cin.tie(0);
	cout << fixed << setprecision(10);
	cerr << fixed << setprecision(4);
	mainmain();
}
catch(...){}


Measured memory_bytes: 18304