#include <bits/stdc++.h>
#define MP make_pair
#define PB push_back
#define int long long
#define st first
#define nd second
#define rd third
#define FOR(i, a, b) for(int i =(a); i <=(b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define REP(i, n) for(int i = 0;i <(n); ++i)
#define VAR(v, i) __typeof(i) v=(i)
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
using namespace std;
template<typename TH> void _dbg(const char* sdbg, TH h) { cerr<<sdbg<<"="<<h<<"\n"; }
template<typename TH, typename... TA> void _dbg(const char* sdbg, TH h, TA... t) {
  while(*sdbg != ',')cerr<<*sdbg++; cerr<<"="<<h<<","; _dbg(sdbg+1, t...);
}
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x) {{cerr <<#x <<" = "; FORE(itt, (x)) cerr <<*itt <<", "; cerr <<"\n"; }}
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define cerr if(0)cout
#endif
#define next ____next
#define prev ____prev
#define left ____left
#define hash ____hash
typedef long long ll;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<pair<int, int> > VPII;
typedef vector<pair<ll, ll> > VPLL;

template<class C> void mini(C&a4, C b4){a4=min(a4, b4); }
template<class C> void maxi(C&a4, C b4){a4=max(a4, b4); }
template<class T1, class T2>
ostream& operator<< (ostream &out, pair<T1, T2> pair) { return out << "(" << pair.first << ", " << pair.second << ")";}
template<class A, class B, class C> struct Triple { A first; B second; C third;
  bool operator<(const Triple& t) const { if (st != t.st) return st < t.st; if (nd != t.nd) return nd < t.nd; return rd < t.rd; } };
template<class T> void ResizeVec(T&, vector<int>) {}
template<class T> void ResizeVec(vector<T>& vec, vector<int> sz) {
  vec.resize(sz[0]); sz.erase(sz.begin()); if (sz.empty()) { return; }
  for (T& v : vec) { ResizeVec(v, sz); }
}
typedef Triple<int, int, int> TIII;
template<class A, class B, class C>
ostream& operator<< (ostream &out, Triple<A, B, C> t) { return out << "(" << t.st << ", " << t.nd << ", " << t.rd << ")"; }
template<class T> ostream& operator<<(ostream& out, vector<T> vec) { out<<"("; for (auto& v: vec) out<<v<<", "; return out<<")"; }

const int N = 1e6 + 5;
const int D = 1e12;
int row[N], col[N];
map<PII, int> mapka;
int vis[N], vis_row[N], vis_col[N];
void Exit(string s) {
  cout<<s<<endl;
  exit(0);
}
int r[N], c[N], a[N];
VI rows[N], cols[N];
TIII hehs[N];
int32_t main() {

  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
  cin.tie(0);
  //double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;
  
  int R, C, n;
  cin>>R>>C>>n;
  REP (i, N) {
    row[i] = col[i] = D;
  }
  REP (i, n) {
    cin>>r[i]>>c[i]>>a[i];
    //hehs[i] = {r, c, a};
    //mapka[{r, c}] = a;
    rows[r[i]].PB(i);
    cols[c[i]].PB(i);
  }
  REP (i, n) {
    if (vis[i] == 0) {
      VI que;
      que.PB(i);
      row[r[i]] = 0;
      col[c[i]] = 0;
      int min_r = 0, min_c = 0;
      vis[i] = 1;
//       vis_row[r[i]] = 1;
//       vis_col[c[i]] = 1;
      for (int ii = 0; ii < SZ(que); ii++) {
        int ind = que[ii];
        int rr = r[ind];
        int cc = c[ind];
        if (!vis_row[rr]) {
          for (auto j : rows[rr]) {
            int nei_c = c[j];
            int cand = a[j] - a[ind] + col[c[ind]];
            if (col[nei_c] != D && col[nei_c] != cand) {
              debug(i, j, nei_c, col[nei_c], cand);
              Exit("No");
            }
            col[nei_c] = cand;
            mini(min_c, col[nei_c]);
            if (!vis[j]) {
              vis[j] = 1;
              que.PB(j);
            }
          }
          vis_row[rr] = 1;
        }
        if (!vis_col[cc]) {
          for (auto j : cols[cc]) {
            int nei_r = r[j];
            int cand = a[j] - a[ind] + row[r[ind]];
            if (row[nei_r] != D && row[nei_r] != cand) {
              debug(i, j, nei_r, row[nei_r], cand);
              Exit("No");
            }
            row[nei_r] = cand;
            mini(min_r, row[nei_r]);
            if (!vis[j]) {
              vis[j] = 1;
              que.PB(j);
            }
          }
          vis_col[cc] = 1;
        }
      }
      if (min_r + min_c + a[i] < 0) {
        Exit("No");
      }
      debug(i, que);
    }
  }
  Exit("Yes");
    
//   for (auto& p : mapka) {
//     int r = p.st.st;
//     int c = p.st.nd;
//     if (mapka.count({r + 1, c})) {
//       int diff = mapka[{r + 1, c}] - mapka[{r, c}];
//       int sign = 1;
//       if (c % 2) {
//         sign *= -1;
//       }
//       int val = diff * sign;
//       if (row[r] != D && row[r] != val) {
//         Exit("No");
//       }
//       row[r] = val;
//     }
//     if (mapka.count({r - 1, c})) {
//       int diff = mapka[{r, c}] - mapka[{r - 1, c}];
//       int sign = 1;
//       if (c % 2) {
//         sign *= -1;
//       }
//       int val = diff * sign;
//       if (row[r - 1] != D && row[r - 1] != val) {
//         Exit("No");
//       }
//       row[r - 1] = val;
//     }
//     if (mapka.count({r, c + 1})) {
//       int diff = mapka[{r, c + 1}] - mapka[{r, c}];
//       int sign = 1;
//       if (r % 2) {
//         sign *= -1;
//       }
//       int val = diff * sign;
//       if (col[c] != D && col[c] != val) {
//         Exit("No");
//       }
//       col[c] = val;
//     }
//     if (mapka.count({r, c - 1})) {
//       int diff = mapka[{r, c}] - mapka[{r, c - 1}];
//       int sign = 1;
//       if (r % 2) {
//         sign *= -1;
//       }
//       int val = diff * sign;
//       if (col[c - 1] != D && col[c - 1] != val) {
//         Exit("No");
//       }
//       col[c - 1] = val;
//     }
//   }
//   Exit("Yes");
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  return 0;
}


Measured memory_bytes: 73728