#include<bits/stdc++.h>

using namespace std;

typedef long long llint;
typedef pair <int, int> pi;

const int MAXN = 100005;

int R, C, n, cnt;
int x[MAXN], y[MAXN], cost[MAXN], bio[MAXN], val[MAXN], mx[MAXN], mn[MAXN];
vector <pi> r[MAXN], v[MAXN];

void dfs (int x, int curr) {
    if (bio[x]) return;
    bio[x] = cnt;
    val[x] = curr;
    mn[cnt] = min(mn[cnt], val[x]);
    for (auto par : v[x]) {
        int sus = par.first, dif = par.second;
        dfs(sus, curr + dif);
    }
}

bool check () {
    for (int i = 1; i <= C; i++) {
        for (auto par : v[i]) {
            int sus = par.first, dif = par.second;
            if (val[sus] - val[i] != dif) return 0;
        }
    }
    for (int i = 1; i <= cnt; i++) {
        if (mx[i] > mn[i]) return 0;
    }
    return 1;
}

int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> R >> C >> n;
    for (int i = 0; i < n; i++) {
        cin >> x[i] >> y[i] >> cost[i];
        r[x[i]].push_back({y[i], cost[i]});
    }
    for (int i = 1; i <= R; i++) {
        sort(r[i].begin(), r[i].end());
        for (int j = 1; j < r[i].size(); j++) {
            int dif = r[i][j].second - r[i][j - 1].second;
            v[r[i][j - 1].first].push_back({r[i][j].first, dif});
            v[r[i][j].first].push_back({r[i][j - 1].first, -dif});
        }
    }
    for (int i = 0; i < n; i++) {
        if (bio[y[i]] == 0) {
            cnt++;
            mn[cnt] = 1e9;
            dfs(y[i], cost[i]);
        } else {
            mx[bio[y[i]]] = max(mx[bio[y[i]]], val[y[i]] - cost[i]);
        }
    }
    if (check()) cout << "Yes"; else cout << "No";
    return 0;
}
