#include <iostream>
#include <queue>
#include <map>
#include <list>
#include <vector>
#include <string>
#include <stack>
#include <limits>
#include <climits>
#include <cassert>
#include <fstream>
#include <cstring>
#include <cmath>
#include <bitset>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <cstdio>
#include <ciso646>
#include <set>
#include <array>

using namespace std;

#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)

#define inf 0x3f3f3f3f
#define PB push_back
#define MP make_pair
#define ALL(a) (a).begin(),(a).end()
#define SET(a,c) memset(a,c,sizeof a)
#define CLR(a) memset(a,0,sizeof a)
#define pii pair<int,int>
#define pcc pair<char,char>
#define pic pair<int,char>
#define pci pair<char,int>
#define VS vector<string>
#define VI vector<int>
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define MIN(a,b) (a>b?b:a)
#define MAX(a,b) (a>b?a:b)
#define pi 2*acos(0.0)
#define INFILE() freopen("in0.txt","r",stdin)
#define OUTFILE()freopen("out0.txt","w",stdout)
#define ll long long
#define ull unsigned long long
#define eps 1e-14
#define FST first
#define SEC second
#define SETUP cin.tie(0), ios::sync_with_stdio(false), cout << setprecision(15)

namespace {
	struct input_returnner {
		int N; input_returnner(int N_ = 0) :N(N_) {}
		template<typename T> operator vector<T>() const { vector<T> res(N); for (auto &a : res) cin >> a; return std::move(res); }
		template<typename T> operator T() const { T res; cin >> res; return res; }
		template<typename T> T operator - (T right) { return T(input_returnner()) - right; }
		template<typename T> T operator + (T right) { return T(input_returnner()) + right; }
		template<typename T> T operator * (T right) { return T(input_returnner()) * right; }
		template<typename T> T operator / (T right) { return T(input_returnner()) / right; }
		template<typename T> T operator << (T right) { return T(input_returnner()) << right; }
		template<typename T> T operator >> (T right) { return T(input_returnner()) >> right; }
	};
	template<typename T> input_returnner in() { return in<T>(); }
	input_returnner in() { return input_returnner(); }
	input_returnner in(int N) { return std::move(input_returnner(N)); }
}

void solve();
/// ---template---
signed main(void) {
	SETUP;
	solve();
	return 0;
}

int dx[] = {1,0,-1,0};
int dy[] = {0,-1,0,1};

const ll INF = LLONG_MAX / 2 - 1;


struct Edge {
	ll t;
	ll c;
	Edge(ll to, ll cost):t(to),c(cost){}
	Edge(){}
};

vector<ll> weigh;
ll R, C;

bool DFS(ll node, vector<vector<Edge> >& edge, ll& xmin, ll& ymin) {
	if (node < R) xmin = min(xmin, weigh[node]);
	else ymin = min(ymin, weigh[node]);
	for (auto &to : edge[node]) {
		if (weigh[to.t] == INF) {
			weigh[to.t] = to.c - weigh[node];
			if (not DFS(to.t, edge, xmin, ymin)) return false;
		}
		else {
			if (weigh[to.t] + weigh[node] != to.c) return false;
		}
	}
	return true;
}

void solve() {
	cin >> R >> C;
	ll N = in();
	weigh.resize(R + C, INF);
	vector<vector<Edge> > edge(R+C);
	REP(i, N) {
		ll r, c, a; cin >> r >> c >> a;
		--r; --c;
		edge[r].emplace_back(R+c,a);
		edge[R+c].emplace_back(r, a);
	}

	bool res = true;
	ll xmin, ymin;
	REP(i, R + C) if(weigh[i] == INF and edge[i].size() > 0) {
		xmin = ymin = numeric_limits<int>::max();
		weigh[i] = 0;
		if (not DFS(i,edge,xmin,ymin) or xmin+ymin < 0) {
			cout << "No" << endl;
			return;
		}
	}
	cout << "Yes" << endl;

}


Measured memory_bytes: 19584