#include <iostream>
#include <string>
#include <cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<iomanip>
#define _USE_MATH_DEFINES
#include <math.h>
#include <functional>
#include<complex>
using namespace std;

#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)

typedef long long ll;
const ll INF = 1e17;
const ll MOD = 1000000007;
const ll MAX = 4000001;
const long double eps = 1E-14;

ll max(ll a, ll b) {
	if (a > b) { return a; }
	return b;
}

ll min(ll a, ll b) {
	if (a > b) { return b; }
	return a;
}

ll gcd(ll a, ll b) {
	if (b == 0) { return a; }
	if (a < b) { return gcd(b, a); }
	return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

struct edge {
	ll ind;
	ll fr;
	ll to;
	ll d;
};

class mint {
	long long x;
public:
	mint(long long x = 0) : x((x% MOD + MOD) % MOD) {}
	mint operator-() const {
		return mint(-x);
	}
	mint& operator+=(const mint& a) {
		if ((x += a.x) >= MOD) x -= MOD;
		return *this;
	}
	mint& operator-=(const mint& a) {
		if ((x += MOD - a.x) >= MOD) x -= MOD;
		return *this;
	}
	mint& operator*=(const  mint& a) {
		(x *= a.x) %= MOD;
		return *this;
	}
	mint operator+(const mint& a) const {
		mint res(*this);
		return res += a;
	}
	mint operator-(const mint& a) const {
		mint res(*this);
		return res -= a;
	}
	mint operator*(const mint& a) const {
		mint res(*this);
		return res *= a;
	}

	mint pow(ll t) const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}

	// for prime MOD
	mint inv() const {
		return pow(MOD - 2);
	}
	mint& operator/=(const mint& a) {
		return (*this) *= a.inv();
	}
	mint operator/(const mint& a) const {
		mint res(*this);
		return res /= a;
	}

	friend ostream& operator<<(ostream& os, const mint& m) {
		os << m.x;
		return os;
	}
};

mint pw(mint a, ll b) {
	if (b == 0) { return 1; }
	mint ret = pw(a, b >> 1);
	ret *= ret;
	if (b & 1) { ret *= a; }
	return ret;
}

typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;

typedef vector<mint> vmint;
typedef vector<vector<mint>> vvmint;
typedef vector<vector<vector<mint>>> vvvmint;

//////////////////////////////////////
ll R, C, N;
vector<vector<edge>> g;
vll val;
vll see;

void dfs(ll u) {
	for (edge e : g[u]) {
		ll v = e.to;
		if (val[v] != -INF) { continue; }
		val[v] = e.d - val[u];
		dfs(v);
	}
	return;
}

pair<ll,ll> minRC(ll u) {
	pair<ll, ll> ret = { INF,INF };
	see[u] = 1;
	if (u <= R) { ret.first = val[u]; }
	else { ret.second = val[u]; }

	for (edge e : g[u]) {
		ll v = e.to;
		if (see[v] == 1) { continue; }
		//cout << v << endl;

		auto p = minRC(v);
		ret.first = min(ret.first, p.first);
		ret.second = min(ret.second, p.second);
	}
	return ret;
}


int main() {
	
	cin >> R >> C >> N;
	vll r(N + 1), c(N + 1), a(N + 1);
	repn(i, N) cin >> r[i] >> c[i] >> a[i];

	g.resize(R + C + 1);

	repn(i, N) {
		g[r[i]].push_back({ i,r[i],R + c[i],a[i] });
		g[R + c[i]].push_back({ i,R + c[i],r[i],a[i] });
	}

	val.assign(R + C + 1, -INF);
	see.assign(R + C + 1, 0);

	repn(v, R+C) {
		if (val[v] == -INF) { val[v] = 0; dfs(v); }
	}

	//repn(v, R + C) { cout << val[v] << endl; }

	repn(i, N) {
		if (val[r[i]] + val[R + c[i]] != a[i]) { cout << "No" << endl; return 0; }
	}

	repn(v, R + C) {
		if (see[v] == 0) {
			auto p = minRC(v);
			//cout <<v<<" "<< p.first << " "<<p.second << endl;
			if (p.first + p.second < 0) { cout << "No" << endl; return 0; }
		}
	}

	cout << "Yes" << endl;

	
}

Measured memory_bytes: 26764