#include <bits/stdc++.h>
 
//    #include <boost/multiprecision/cpp_int.hpp>
 #define int long long
 #define inf  1000000007
 #define pa pair<int,int>
 #define ll long long
 #define pal pair<double,double>
 #define ppap pair<pa,int>
  #define PI 3.14159265358979323846
  #define paa pair<int,char>
  #define  mp make_pair
  #define  pb push_back
  #define EPS (1e-8)
                                          
    int dx[8]={0,1,0,-1,1,1,-1,-1};
    int dy[8]={1,0,-1,0,-1,1,1,-1};
                                            using namespace std;
                                   			class pa3{
                                            	public:
                                            	int x;
                                   				int y,z;
                                            	pa3(int x=0,int y=0,int z=0):x(x),y(y),z(z) {}
                                            	bool operator < (const pa3 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		 return z<p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                   				bool operator > (const pa3 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		 return z>p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa3 &p) const{
                                            		return x==p.x && y==p.y && z==p.z;
                                            	}
                                            		bool operator != (const pa3 &p) const{
                                            			return !( x==p.x && y==p.y && z==p.z);
                                            	}
                                            
                                            };
                                            
                                            class pa4{
                                            	public:
                                            	int x;
                                            	int y,z,w;
                                            	pa4(int x=0,int y=0,int z=0,int w=0):x(x),y(y),z(z),w(w) {}
                                            	bool operator < (const pa4 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		if(z!=p.z)return z<p.z;
                                            		return w<p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator > (const pa4 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		if(z!=p.z)return z>p.z;
                                            		return w>p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa4 &p) const{
                                            		return x==p.x && y==p.y && z==p.z &&w==p.w;
                                            	}
                                            		
                                            
                                            };
                                            class pa2{
                                            	public:
                                            	int x,y;
                                            	pa2(int x=0,int y=0):x(x),y(y) {}
                                            	pa2 operator + (pa2 p) {return pa2(x+p.x,y+p.y);}
                                            	pa2 operator - (pa2 p) {return pa2(x-p.x,y-p.y);}
                                            	bool operator < (const pa2 &p) const{
                                            		return y != p.y ? y<p.y: x<p.x;
                                            	}
                                            	bool operator > (const pa2 &p) const{
                                            		return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa2 &p) const{
                                            		return abs(x-p.x)==0 && abs(y-p.y)==0;
                                            	}
                                            	bool operator != (const pa2 &p) const{
                                            		return !(abs(x-p.x)==0 && abs(y-p.y)==0);
                                            	}
                                            		
                                            
                                            };
                                            
 
                      
                                string itos( int i ) {
                                ostringstream s ;
                                s << i ;
                                return s.str() ;
                                }
                                 
                                int gcd(int v,int b){
                                	if(v>b) return gcd(b,v);
                                	if(v==b) return b;
                                	if(b%v==0) return v;
                                	return gcd(v,b%v);
                                }
                 
                            
                                int mod;
int extgcd(int a, int b, int &x, int &y) {
    if (b == 0) {
        x = 1;
        y = 0;
        return a;
    }
    int d = extgcd(b, a%b, y, x);
    y -= a/b * x;
    return d;
}
pa operator+(const pa & l,const pa & r) {   
    return {l.first+r.first,l.second+r.second};                                    
}    
pa operator-(const pa & l,const pa & r) {   
    return {l.first-r.first,l.second-r.second};                                    
}  
                                
                int pr[1000010];
                int inv[1000010];
                
                int beki(int wa,int rr,int warukazu){
                	if(rr==0) return 1%warukazu;
                	if(rr==1) return wa%warukazu;
                	wa%=warukazu;
                	if(rr%2==1) return ((ll)beki(wa,rr-1,warukazu)*(ll)wa)%warukazu;
                	ll zx=beki(wa,rr/2,warukazu);
                	return (zx*zx)%warukazu;
                }
 
                
    			int comb(int nn,int rr){
    				if(rr<0 || rr>nn || nn<0) return 0;
    				int r=pr[nn]*inv[rr];
    				r%=mod;
    				r*=inv[nn-rr];
    				r%=mod;
    				return r;
    			}
               
                void gya(int ert){
                	pr[0]=1;
                	for(int i=1;i<=ert;i++){
                		pr[i]=(pr[i-1]*i)%mod;
                	}
                		inv[ert]=beki(pr[ert],mod-2,mod);
                	for(int i=ert-1;i>=0;i--){
                		inv[i]=inv[i+1]*(i+1)%mod;
                	}
                }
                
              //   cin.tie(0);
    		//	ios::sync_with_stdio(false);
    			//priority_queue<pa3,vector<pa3>,greater<pa3>> pq;            
                 //sort(ve.begin(),ve.end(),greater<int>());
 //   mt19937(clock_per_sec);
  //  mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()) ;
      
       
       
                               //----------------kokomade tenpure------------
struct unionfind{
	private:
	public:
	
vector<int> par,ranks,kosuu;
	
	void shoki(int N){
		par.resize(N+1,0);
		ranks.resize(N+1,0);
		kosuu.resize(N+1,1);
		for(int i=0;i<=N;i++){
			par[i]=i;
		}
	}

	int root(int x){
		return par[x]==x ? x : par[x]=root(par[x]);
	}

	bool same(int x,int y){
		return root(x)==root(y);
	}
	bool is_root(int x){
		return x==root(x);
	}
	void unite(int x,int y){
 		x=root(x);
	 	y=root(y);
		int xx=kosuu[x],yy=kosuu[y];
	 	if(x==y) return;
		if(ranks[x]<ranks[y]){
			par[x]=y;
			kosuu[y]=yy+xx;
		}
	 	else {
			par[y]=x;
			if(ranks[x]==ranks[y]) ranks[x]=ranks[x]+1;
	 		kosuu[x]=yy+xx;
	 	}
		return;
	}
};

int val[200020];
int inff=inf*10000000ll;
 	vector<pa> G[200020];
 	
void dfs(int r,int p,int v){
	if(val[r]!=inff){
		if(val[r]!=v){
			cout<<"No"<<endl;
			exit(0);
		}
		return;
	}
	val[r]=v;
	for(auto w:G[r])if(w.first!=p){
		dfs(w.first,r,w.second-v);
	}
}
 	
 	int a[200020][2];
 	
 signed main(){

   cin.tie(0);
	ios::sync_with_stdio(false);

 	int r,c;
 	cin>>r>>c;
 	for(int i=0;i<r+c;i++)val[i]=inff,a[i][0]=inff,a[i][1]=inff;
 	int n;
 	cin>>n;
 	
 	unionfind uf;
 	uf.shoki(r+c+4);
 	
 	for(int i=0;i<n;i++){
 		int x,y,z;
 		cin>>x>>y>>z;
 		x--,y--;
 		G[x].pb(mp(r+y,z));
 		G[r+y].pb(mp(x,z));
 		uf.unite(x,r+y);
 	}
 	for(int i=0;i<r+c;i++)if(val[i]==inff) dfs(i,i,0);
 	
 	for(int i=0;i<r+c;i++){
 		int rr=uf.root(i);
 	//	cout<<val[i]<<" "<<r<<" "<<uf.kosuu[r]<<endl;
 		
 		if(uf.kosuu[rr]==1) continue;
 		
 		if(i<r)a[rr][0]=min(a[rr][0],val[i]);
 		else a[rr][1]=min(a[rr][1],val[i]);
 	//	cout<<a[rr][0]<<" "<<a[rr][1]<<endl;
 		
 	}
 	
 	for(int i=0;i<r+c;i++)if(a[i][0]!=inff){
 	//	cout<<a[i][0]+a[i][1]<<endl;
 		if(a[i][0]+a[i][1]<0){
 			cout<<"No"<<endl;
 			return 0;
 		}
 	}

 	cout<<"Yes"<<endl;
return 0;
 
 }
 

Measured memory_bytes: 25088