import std.stdio;
import std.string;
import std.conv;
import std.typecons;
import std.algorithm;
import std.functional;
import std.bigint;
import std.numeric;
import std.array;
import std.math;
import std.range;
import std.container;
import std.ascii;
void times(alias pred)(int n) {
    foreach(i; 0..n) pred();
}
auto rep(alias pred, T = typeof(pred()))(int n) {
    T[] res = new T[n];
    foreach(ref e; res) e = pred();
    return res;
}

void main() {
    int R, C, N;
    int[Pos] aa;
    void main() {
        readf("%d %d\n%d\n", &R, &C, &N);
        N.times!({
            int r, c, a;
            readf("%d %d %d\n", &r, &c, &a);
            r--; c--;
            aa[Pos(r, c)] = a;
        });
    
        writeln("Yes");

    }
}
