/*+lmake
 * DEFINE += WAAUTOMATON
 */
#include <bits/stdc++.h>
#ifdef WAAUTOMATON
#define debug(args...)                                                                             \
    {                                                                                              \
        dbg, args;                                                                                 \
        cerr << endl;                                                                              \
    }
#define massert(x) assert(x)
#else
#define debug(args...) // Just strip off all debug tokens
#define massert(x)
#endif
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> pii;
struct debugger
{
    template <typename T>
    debugger &operator,(const T &v)
    {
        std::cerr << v << " ";
        return *this;
    }
} dbg;

void iopen()
{
    static bool isOpen = false;
    if (!isOpen) {
        isOpen = true;
#ifdef WAAUTOMATON
        freopen("in.txt", "r", stdin);
#endif
    }
}
template <size_t _I_Buffer_Size = 1 << 23, size_t _O_Buffer_Size = 1 << 23>
struct IO_Tp
{
    char _I_Buffer[_I_Buffer_Size];
    char *_I_pos;
    const char *_I_end;

    char _O_Buffer[_O_Buffer_Size];
    char *_O_pos;
    const char *_O_end;

    IO_Tp()
        : _I_pos(_I_Buffer)
        , _O_pos(_O_Buffer)
        , _I_end(_I_Buffer + _I_Buffer_Size)
        , _O_end(_O_Buffer + _O_Buffer_Size)
    {
    }

    ~IO_Tp() { fwrite(_O_Buffer, 1, _O_pos - _O_Buffer, stdout); }

    inline char getchar()
    {
        char res = *_I_pos;
        nextchar();
        return res;
    }

    inline bool is_digit(const char ch) { return '0' <= ch && ch <= '9'; }

    inline void nextchar()
    {
        ++_I_pos;
        if (_I_pos == _I_end) {
            fread(_I_Buffer, 1, _I_Buffer_Size, stdin);
            _I_pos = _I_Buffer;
        }
    }

    template <typename Int>
    inline IO_Tp &operator>>(Int &res)
    {
        res = 0;
        int k = 1;
        while (!is_digit(*_I_pos)) {
            if (*_I_pos == '-')
                k = -1;
            nextchar();
        }
        do {
            (res *= 10) += (*_I_pos) - '0';
            nextchar();
        } while (is_digit(*_I_pos));
        res *= k;
        return *this;
    }

    inline IO_Tp &operator>>(char &res)
    {
        res = *_I_pos;
        nextchar();
        return *this;
    }

    inline void putchar(char x)
    {
        if (_O_pos == _O_end) {
            fwrite(_O_Buffer, 1, _O_pos - _O_Buffer, stdout);
            _O_pos = _O_Buffer;
        }
        *_O_pos++ = x;
    }
    template <typename Int>
    inline IO_Tp &operator<<(Int n)
    {
        if (n < 0) {
            putchar('-');
            n = -n;
        }
        static char _buf[20];
        char *_pos(_buf);
        do
            *_pos++ = '0' + n % 10;
        while (n /= 10);
        while (_pos != _buf)
            putchar(*--_pos);
        return *this;
    }

    inline IO_Tp &operator<<(char ch)
    {
        putchar(ch);
        return *this;
    }

    inline IO_Tp &operator<<(const char *s)
    {
        while (*s != 0) {
            putchar(*s);
            ++s;
        }
        return *this;
    }
};
IO_Tp<> IO;
const int MAXN = 200000;
vector<pii> g[MAXN + 10];
bool vis[MAXN + 10];
LL L, R;
bool flag;
LL vx[MAXN + 10];
int r, c, n;
void dfs(int now, LL v)
{
    if (!flag)
        return;
    if (!vis[now]) {
        if (vx[now] != v) {
            flag = false;
            return;
        }
		return;
    }
    vis[now] = false;
    vx[now] = v;
    if (now <= r)
        L = max(L, v);
    else
        R = min(R, v);
    for (auto i : g[now]) {
        dfs(i.first, v + i.second);
        if (!flag)
            return;
    }
}
int main()
{
    iopen();
    int T;
   T=1;
    while (T--) {
        IO >> r >> c >> n;
        for (int i = 1; i <= r + c; ++i) {
            g[i].clear();
        }
        for (int i = 1; i <= n; ++i) {
            int x, y, v;
            IO >> x >> y >> v;
            g[x].push_back(pii(y + r, v));
            g[y + r].push_back(pii(x, -v));
        }
        memset(vis, true, sizeof(vis));
        memset(vx, 0, sizeof(vx));
        flag = true;
        for (int i = 1; i <= r + c; ++i) {
            if (vis[i]) {
                L = LLONG_MIN;
                R = LLONG_MAX;
                dfs(i, 0);
                if (L > R) {
                    flag = false;
                    break;
                }
            }
        }
        if (flag) {
            IO << "Yes\n";
        } else {
            IO << "No\n";
        }
    }
    return 0;
}


Measured memory_bytes: 18816