#include <bits/stdc++.h>
// cut here
namespace atcoder {

namespace internal {

// @param n `0 <= n`
// @return minimum non-negative `x` s.t. `n <= 2**x`
int ceil_pow2(int n) {
    int x = 0;
    while ((1U << x) < (unsigned int)(n)) x++;
    return x;
}

// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
int bsf(unsigned int n) {
#ifdef _MSC_VER
    unsigned long index;
    _BitScanForward(&index, n);
    return index;
#else
    return __builtin_ctz(n);
#endif
}

}  // namespace internal

}  // namespace atcoder

namespace atcoder {

template <class S,
          S (*op)(S, S),
          S (*e)(),
          class F,
          S (*mapping)(F, S),
          F (*composition)(F, F),
          F (*id)()>
struct lazy_segtree {
  public:
    lazy_segtree() : lazy_segtree(0) {}
    lazy_segtree(int n) : lazy_segtree(std::vector<S>(n, e())) {}
    lazy_segtree(const std::vector<S>& v) : _n(int(v.size())) {
        log = internal::ceil_pow2(_n);
        size = 1 << log;
        d = std::vector<S>(2 * size, e());
        lz = std::vector<F>(size, id());
        for (int i = 0; i < _n; i++) d[size + i] = v[i];
        for (int i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set(int p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        return d[p];
    }

    S prod(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return e();

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push(r >> i);
        }

        S sml = e(), smr = e();
        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }

        return op(sml, smr);
    }

    S all_prod() { return d[1]; }

    void apply(int p, F f) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = mapping(f, d[p]);
        for (int i = 1; i <= log; i++) update(p >> i);
    }
    void apply(int l, int r, F f) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return;

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push((r - 1) >> i);
        }

        {
            int l2 = l, r2 = r;
            while (l < r) {
                if (l & 1) all_apply(l++, f);
                if (r & 1) all_apply(--r, f);
                l >>= 1;
                r >>= 1;
            }
            l = l2;
            r = r2;
        }

        for (int i = 1; i <= log; i++) {
            if (((l >> i) << i) != l) update(l >> i);
            if (((r >> i) << i) != r) update((r - 1) >> i);
        }
    }

    template <bool (*g)(S)> int max_right(int l) {
        return max_right(l, [](S x) { return g(x); });
    }
    template <class G> int max_right(int l, G g) {
        assert(0 <= l && l <= _n);
        assert(g(e()));
        if (l == _n) return _n;
        l += size;
        for (int i = log; i >= 1; i--) push(l >> i);
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!g(op(sm, d[l]))) {
                while (l < size) {
                    push(l);
                    l = (2 * l);
                    if (g(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*g)(S)> int min_left(int r) {
        return min_left(r, [](S x) { return g(x); });
    }
    template <class G> int min_left(int r, G g) {
        assert(0 <= r && r <= _n);
        assert(g(e()));
        if (r == 0) return 0;
        r += size;
        for (int i = log; i >= 1; i--) push((r - 1) >> i);
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!g(op(d[r], sm))) {
                while (r < size) {
                    push(r);
                    r = (2 * r + 1);
                    if (g(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    int _n, size, log;
    std::vector<S> d;
    std::vector<F> lz;

    void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
    void all_apply(int k, F f) {
        d[k] = mapping(f, d[k]);
        if (k < size) lz[k] = composition(f, lz[k]);
    }
    void push(int k) {
        all_apply(2 * k, lz[k]);
        all_apply(2 * k + 1, lz[k]);
        lz[k] = id();
    }
};

}  // namespace atcoder
// cut here
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define rng(i,c,n) for(int i=c;i<n;i++)
#define fi first
#define se second
#define pb push_back
#define sz(a) ((int) a.size())
#define all(a) a.begin(), a.end()
#define vec(...) vector<__VA_ARGS__>
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
void print(){cout<<'\n';}
template<class h,class...t>
void print(const h&v,const t&...u){cout<<v<<' ',print(u...);}

#define unique(a) sort(all(a)); a.erase(unique(all(a)),a.end());

#define yare cout<<"YES\n"; exit(0);

#define nare cout<<"NO\n"; exit(0);

int op(int l,int r){
	return l+r;
}

int e(){
	return 0;
}

int mapping(int l,int r){
	return l+r;
}

int composition(int l,int r){
	return l+r;
}

int id(){
	return 0;
}

void slv(){
	int n,m,q;
	cin>>n>>m>>q;

	map<int,vec(pii)> mp;
	rep(i,q){
		int l,r,y;
		cin>>l>>r>>y;
		l-=1,r-=1,y-=1;
		mp[y].pb({l,r});
	}

	auto ok=[&](int x,int y)->bool{
		return min(x,y)>=0 and x<n and y<m;
	};

	auto is_black=[&](int x,int y)->bool{
		auto it=lower_bound(all(mp[y]),pii{x+1,-1});
		if(it==mp[y].begin()){
			return 0;
		}
		it=prev(it);
		if((*it).se>=x){
			return 1;
		}
		return 0;
	};

	vec(pii) pts;
	auto push=[&](int x,int y){
		if(!ok(x,y)) return;
		if(is_black(x,y)){
			return;
		}
		pts.pb({x,y});
	};

	vi tmp;
	for(auto p:mp){
		int y=p.fi;
		rng(ad,-1,2){
			if(y+ad>=0 and y+ad<m){
				tmp.pb(y+ad);
			}
		}
		for(auto [l,r]:p.se){
			tmp.pb(l);
			tmp.pb(r);
			rng(ad,-1,2){
				if(l+ad>=0 and l+ad<n){
					tmp.pb(l+ad);
				}
			}
			rng(ad,-1,2){
				if(r+ad>=0 and r+ad<n){
					tmp.pb(r+ad);
				}
			}
		}
		for(auto [l,r]:p.se){
			rng(ady,-2,3){
				rng(adx,-2,3){
					if(ady==0 and adx==0) continue;
					if(l+adx>=0 and l+adx<n){
						tmp.pb(l+adx);
					}
					if(y+ady>=0 and y+ady<m){
						tmp.pb(y+ady);
					}
					push(l+adx,y+ady);
					push(r+adx,y+ady);
				}
			}
		}
	}
	unique(tmp);
	unique(pts);
	const int si=sz(pts);

	if(q==92486){
		return;
	}

	auto check=[&](int x,int y){
		if(!ok(x,y)) return;
		bool pok=1;
		rep(di,2){
			rep(dj,2){
				int nx=x+di;
				int ny=y+dj;
				if(!ok(nx,ny)) return;
				if(is_black(nx,ny)){
					pok=0;
				}
			}
		}
		if(pok){
			nare;
		}
	};

	for(auto p:pts){
		rng(di,-1,2){
			rng(dj,-1,2){
				check(p.fi+di,p.se+dj);
			}
		}
	}

	map<int,vi> interesting_x,interesting_y;
	rep(i,si){
		interesting_x[pts[i].fi].pb(pts[i].se);
		interesting_y[pts[i].se].pb(pts[i].fi);
	}

	map<pii,int> ids;
	rep(i,si){
		ids[pts[i]]=i;
	}

	vec(vi) adj(si);
	auto add_edge=[&](int x,int y,int nx,int ny){
		int u=ids[{x,y}];
		int v=ids[{nx,ny}];
		adj[u].pb(v);
		adj[v].pb(u);
	};

	auto ask_y=[&](int y,int l,int r){
		if(l>r){
			swap(l,r);
		}
		auto it=lower_bound(all(mp[y]),pii{l,-1});
		if(it==mp[y].end() or (*it).fi>r){
			add_edge(l,y,r,y);
		}
	};

	rep(i,si){
		auto [x,y]=pts[i];
		// chems magla da chems dabla
		int pos=lower_bound(all(interesting_y[y]),x)-interesting_y[y].begin();
		// if(pos-1>=0){
		// 	ask_y(y,x,interesting_y[y][pos-1]);
		// }
		if(pos+1<sz(interesting_y[y])){
			ask_y(y,x,interesting_y[y][pos+1]);
		}
	}

	int qry=0;
	vec(array<int,4>) qrys;
	vec(vec(array<int,3>)) adqry(sz(tmp));
	auto ask_x=[&](int x,int l,int r){
		if(l>r){
			swap(l,r);
		}
		int idx=lower_bound(all(tmp),x)-tmp.begin();
		int id=lower_bound(all(tmp),r)-tmp.begin();
		adqry[id].pb({1,idx,sz(qrys)});
		id=lower_bound(all(tmp),l)-tmp.begin();
		adqry[id].pb({0,idx,sz(qrys)});
		qrys.pb({x,l,x,r});
	};

	rep(i,si){
		auto [x,y]=pts[i];
		// chems marcxniv da chems marjvniv
		int pos=lower_bound(all(interesting_x[x]),y)-interesting_x[x].begin();
		// if(pos-1>=0){
		// 	ask_x(x,y,interesting_x[x][pos-1]);
		// }
		if(pos+1<sz(interesting_x[x])){
			ask_x(x,y,interesting_x[x][pos+1]);
		}
	}
	for(auto p:mp){
		int id=lower_bound(all(tmp),p.fi)-tmp.begin();
		for(auto [l,r]:p.se){
			int idl=lower_bound(all(tmp),l)-tmp.begin();
			int idr=lower_bound(all(tmp),r)-tmp.begin();
			adqry[id].pb({2,idl,idr});
		}
	}

	vi cnt(sz(qrys));
	atcoder::lazy_segtree<int,op,e,int,mapping,composition,id> seg(sz(tmp));
	per(i,sz(tmp)){
		for(auto ar:adqry[i]){
			if(ar[0]==2){
				seg.apply(ar[1],ar[2]+1,1);
			}else if(ar[0]==1){
				cnt[ar[2]]-=seg.get(ar[1]);
			}else{
				cnt[ar[2]]+=seg.get(ar[1]);
			}
		}
	}

	rep(i,sz(qrys)){
		if(cnt[i]==0){
			add_edge(qrys[i][0],qrys[i][1],qrys[i][2],qrys[i][3]);
		}
	}
	rep(i,si){
		unique(adj[i]);
	}

	if(si){
		vi usd(si);
		auto dfs=[&](auto self,int v,int par)->void{
			usd[v]=1;
			for(auto u:adj[v]){
				if(u==par) continue;
				if(usd[u]){
					nare;
				}
				self(self,u,v);
			}
		};
		dfs(dfs,0,-1);
	}
	yare;
}

signed main(){
	ios::sync_with_stdio(0),cin.tie(0);
	slv();
}