#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
#define int ll
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector< vi > vvi;
typedef vector< vvi > vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef RUS_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";


template <class T0, class T1>
inline ostream & operator << (ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1>
inline istream & operator >> (istream &in, pair<T0, T1> &a) {
    return in >> a.first >> a.second;
}

template <class T0, class T1, class T2>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " <<  get<3>(a) << "}";
}

template<class T>
inline ostream & operator << (ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())
        out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}


void smain();



signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
#ifdef RUS_HOME
    freopen("input", "r", stdin);
    //freopen("output.txt", "w", stdout);
    clock_t start = clock();
#endif
    cout << setprecision(12) << fixed;
    smain();
#ifdef RUS_HOME
    cout << "\n\n\n\nTOTAL EXECUTION TIME: " << float( clock () - start ) /  CLOCKS_PER_SEC << endl;
#endif
    return 0;
}

const int MOD=1e9+7,N=1e5+100,M=18,oo=1e18;

vpi vec[N][2],g[N],kek;
int chis[N][2];
int lol[N];
bool used[N];
int n,m,k;

void dfs(int v,int zn){
    used[v]=true;
    kek.push_back({zn,v});
    lol[v]=zn;
    for(auto to:g[v]){
        int u=to.first,diff=to.second;
        if(used[u]){
            if(zn-diff!=lol[u]){
                cout<<"No";
                exit(0);
            }
        }else{
            dfs(u,zn-diff);
        }
    }
}


void smain() {
    cin>>n>>m>>k;
    for(int i=1;i<N;i++){
        chis[i][0]=chis[i][1]=oo;
    }
    for(int i=0;i<k;i++){
        int a,b,c;
        cin>>a>>b>>c;
        inmin(chis[a][0],c);
        inmin(chis[b][1],c);
        vec[a][0].push_back({b,c});
        vec[b][1].push_back({a,c});
    }
    n=max(n,m);
    for(int h=0;h<2;h++){
        for(int i=1;i<=n;i++){
            sort(ALL(vec[i][h]));
            for(int j=1;j<SZ(vec[i][h]);j++){
                int v=vec[i][h][j-1].first,u=vec[i][h][j].first,
                        diff=vec[i][h][j].second-vec[i][h][j-1].second;
                g[u].push_back({v,diff});
                g[v].push_back({u,-diff});
            }
        }
        for(int i=1;i<=n;i++){
            if(!used[i]){
                kek.clear();
                dfs(i,0);
                sort(ALL(kek));
                for(int j=SZ(kek)-1;j>=0;j--){
                    kek[j].first-=kek[0].first;
                    if(chis[kek[j].second][1-h]<kek[j].first){
                        cout<<"No";
                        exit(0);
                    }
                }
            }
        }
        for(int i=1;i<=n;i++){
            g[i].clear();
            used[i]=false;
        }
    }
    cout<<"Yes";







}



Measured memory_bytes: 26144