#if 0
cat <<EOF >mistaken-paste
#endif
// thanks for @rsk0315_h4x

#pragma GCC diagnostic ignored "-Wincompatible-pointer-types"
#define _USE_MATH_DEFINES

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <math.h>
#include <time.h>

#define BIG 2000000007
#define VERYBIG 2000000000000007LL

#define MOD 1000000007
#define FOD  998244353
typedef uint64_t ull;
typedef  int64_t sll;

#define N_MAX 1000000

#ifdef __cplusplus
#include <queue>
#include <stack>
#include <tuple>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <functional>
#include <array>

using std::queue;
using std::priority_queue;
using std::stack;
using std::tuple;
using std::set;
using std::map;
using std::vector;
using std::greater;
using std::pair;
using std::string;

#endif

typedef struct {
	int32_t a;
	int32_t b;
} hw;

typedef struct {
	sll a;
	sll b;
} hwll;

typedef struct {
	sll a;
	sll b;
	sll c;
} hwllc;

typedef struct {
	hwll a;
	hwll b;
} linell;

ull n, m;
ull h, w;
ull k;
ull q;
sll va, vb, vc, vd, ve, vf;
ull ua, ub, uc, ud, ue, uf;
long double vra, vrb, vrc;
double vda, vdb, vdc;
char ch, dh;

ull umin (ull x, ull y) {
	return (x < y) ? x : y;
}

ull umax (ull x, ull y) {
	return (x > y) ? x : y;
}

sll smin (sll x, sll y) {
	return (x < y) ? x : y;
}

sll smax (sll x, sll y) {
	return (x > y) ? x : y;
}

ull gcd (ull x, ull y) {
	if (x < y) {
		return gcd(y, x);
	} else if (y == 0) {
		return x;
	} else {
		return gcd(y, x % y);
	}
}

ull bitpow (ull a, ull x, ull modulo) {
	ull result = 1;
	while (x) {
		if (x & 1) {
			result *= a;
			result %= modulo;
		}
		x /= 2;
		a = (a * a) % modulo;
	}
	return result;
}

ull divide (ull a, ull b, ull modulo) {
	return (a * bitpow(b, modulo - 2, modulo)) % modulo;
}

ull udiff (ull a, ull b) {
	if (a >= b) {
		return a - b;
	} else {
		return b - a;
	}
}

sll sdiff (sll a, sll b) {
	if (a >= b) {
		return a - b;
	} else {
		return b - a;
	}
}

int bitcount (ull n) {
	int result = 0;
	while (n) {
		if (n & 1) result++;
		n /= 2;
	}
	return result;
}

// double distance (sll x1, sll y1, sll x2, sll y2) {
// 	double xdist2, ydist2, origindist, dist;

// 	xdist2 = (x1 - x2) * (x1 - x2);
// 	ydist2 = (y1 - y2) * (y1 - y2);
// 	return sqrt(xdist2 + ydist2);
// }

int32_t pullcomp (const void *left, const void *right) {
	ull l = *(ull*)left;
	ull r = *(ull*)right;
	if (l < r) {
		return -1;
	}
	if (l > r) {
		return +1;
	}
	return 0;
}

int32_t psllcomp (const void *left, const void *right) {
	sll l = *(sll*)left;
	sll r = *(sll*)right;
	if (l < r) {
		return -1;
	}
	if (l > r) {
		return +1;
	}
	return 0;
}

int32_t pcharcomp (const void *left, const void *right) {
	char l = *(char*)left;
	char r = *(char*)right;
	if (l < r) {
		return -1;
	}
	if (l > r) {
		return +1;
	}
	return 0;
}

int32_t pdoublecomp (const void *left, const void *right) {
	double l = *(double*)left;
	double r = *(double*)right;
	if (l < r) {
		return -1;
	}
	if (l > r) {
		return +1;
	}
	return 0;
}

int32_t pstrcomp (const void *left, const void *right) {
	char* l = *(char**)left;
	char* r = *(char**)right;

	return strcmp(l, r);
}

int32_t phwllABcomp (const void *left, const void *right) {
	hwll l = *(hwll*)left;
	hwll r = *(hwll*)right;
	if (l.a < r.a) {
		return -1;
	}
	if (l.a > r.a) {
		return +1;
	}
	if (l.b < r.b) {
		return -1;
	}
	if (l.b > r.b) {
		return +1;
	}
	return 0;
}

int32_t phwllREVcomp (const void *left, const void *right) {
	hwll l = *(hwll*)left;
	hwll r = *(hwll*)right;
	if (l.b < r.b) {
		return -1;
	}
	if (l.b > r.b) {
		return +1;
	}
	if (l.a < r.a) {
		return -1;
	}
	if (l.a > r.a) {
		return +1;
	}
	return 0;
}

int32_t ptriplecomp (const void *left, const void *right) {
	hwllc l = *(hwllc*)left;
	hwllc r = *(hwllc*)right;

	if (l.a < r.a) {
		return -1;
	}
	if (l.a > r.a) {
		return +1;
	}
	if (l.b < r.b) {
		return -1;
	}
	if (l.b > r.b) {
		return +1;
	}
	if (l.c < r.c) {
		return -1;
	}
	if (l.c > r.c) {
		return +1;
	}
	return 0;
}

int32_t ptripleREVcomp (const void *left, const void *right) {
	hwllc l = *(hwllc*)left;
	hwllc r = *(hwllc*)right;

	if (l.b < r.b) {
		return -1;
	}
	if (l.b > r.b) {
		return +1;
	}
	if (l.a < r.a) {
		return -1;
	}
	if (l.a > r.a) {
		return +1;
	}
	if (l.c < r.c) {
		return -1;
	}
	if (l.c > r.c) {
		return +1;
	}
	return 0;
}

int32_t pquadcomp (const void *left, const void *right) {
	linell l = *(linell*)left;
	linell r = *(linell*)right;

	sll ac = phwllABcomp(&(l.a), &(r.a));
	if (ac) return ac;
	sll bc = phwllABcomp(&(l.b), &(r.b));
	if (bc) return bc;

	return 0;
}

bool isinrange (sll left, sll x, sll right) {
	return (left <= x && x <= right);
}

bool isinrange_soft (sll left, sll x, sll right) {
	return (left <= x && x <= right) || (left >= x && x >= right);
}

sll a[N_MAX];
// ull a[N_MAX];
// sll a[3001][3001];
sll b[N_MAX];
// sll b[3001][3001];
sll c[N_MAX];
// sll d[N_MAX];
// sll e[N_MAX];
char s[N_MAX + 1];
// char s[3010][3010];
char t[N_MAX + 1];
// char t[3010][3010];
hwll xy[N_MAX];
hwllc tup[N_MAX];
// sll table[1000][1000];

hwllc g1[N_MAX], g2[N_MAX];
ull glen1 = 0, glen2 = 0;
ull gin1[N_MAX], gin2[N_MAX];
bool check1[N_MAX], check2[N_MAX];
sll c1[N_MAX], c2[N_MAX];
sll min1 = VERYBIG, min2 = VERYBIG;

bool dfs1 (sll v) {
	check1[v] = true;

	for (sll i = gin1[v]; i < gin1[v + 1]; i++) {
		sll u = g1[i].b;

		if (check1[u]) {
			if (c1[v] + g1[i].c != c1[u]) return false;
		} else {
			c1[u] = c1[v] + g1[i].c;
			if (c1[u] < min1) min1 = c1[u];
			if (!dfs1(u)) return false;
		}
	}
	return true;
}
bool dfs2 (sll v) {
	check2[v] = true;

	for (sll i = gin2[v]; i < gin2[v + 1]; i++) {
		sll u = g2[i].b;

		if (check2[u]) {
			if (c2[v] + g2[i].c != c2[u]) return false;
		} else {
			c2[u] = c2[v] + g2[i].c;
			if (c2[u] < min2) min2 = c2[u];
			if (!dfs2(u)) return false;
		}
	}
	return true;
}

ull solve () {
	sll i, j, ki, li;
	ull result = 0;
	// sll result = 0;
	double dresult = 0;
	// ull maybe = 0;
	sll maybe = 0;
	// ull sum = 0;
	sll sum = 0;
	sll item;
	ull *dpcell;

	for (i = 0; i < n; i++) {
		xy[i].a = a[i];
		xy[i].b = i;
	}
	qsort(xy, n, sizeof(hwll), phwllABcomp);
	for (i = 1; i < n; i++) {
		if (xy[i - 1].a != xy[i].a) continue;

		ull v = xy[i - 1].b, u = xy[i].b;

		hwllc xl = {b[v], b[u], c[u] - c[v]};
		hwllc xr = {b[u], b[v], c[v] - c[u]};
		g1[glen1++] = xl;
		g1[glen1++] = xr;
	}
	qsort(g1, glen1, sizeof(hwllc), ptriplecomp);

	for (i = 0; i < n; i++) {
		xy[i].a = b[i];
		xy[i].b = i;
	}
	qsort(xy, n, sizeof(hwll), phwllABcomp);
	for (i = 1; i < n; i++) {
		if (xy[i - 1].a != xy[i].a) continue;

		ull v = xy[i - 1].b, u = xy[i].b;

		hwllc xl = {a[v], a[u], c[u] - c[v]};
		hwllc xr = {a[u], a[v], c[v] - c[u]};
		g2[glen2++] = xl;
		g2[glen2++] = xr;
	}
	qsort(g2, glen2, sizeof(hwllc), ptriplecomp);

	i = j = 0;
	while (i < w) {
		gin1[i] = j;
		while (j < glen1 && g1[j].a == i) j++;
		i++;
	}
	gin1[w] = glen1;
	i = j = 0;
	while (i < h) {
		gin2[i] = j;
		while (j < glen2 && g2[j].a == i) j++;
		i++;
	}
	gin2[h] = glen2;

	for (i = 0; i < n; i++) {
		if (!check1[b[i]] || !check2[a[i]]) {
			min1 = c1[b[i]] = 0;
			min2 = c2[a[i]] = c[i];
			if (!dfs1(b[i]) || !dfs2(a[i])) goto fail;
			if (min1 + min2 < 0) goto fail;
		}
	}

	// sll downx = (glen1 ? c[g1[0].a] - c1[g1[0].a] + min1 : VERYBIG);
	// sll downy = (glen1 ? c[g1[0].a] - c2[g1[0].a] + min2 : VERYBIG);
	// sll minv = c[g1[0].a] - downx - downy;
	// for (i = 0; i < n; i++) {
	// 	// printf("%lld+%lld.\n", c1[b[i]], c2[a[i]]);
	// 	if (check1[b[i]] || check2[a[i]]) {
	// 		if (c1[b[i]] + c2[a[i]] != c[i]) {
	// 			// fprintf(stderr, "WTF\n");
	// 			abort();
	// 			goto fail;
	// 		}
	// 		// if (c2[a[i]] + min1 < 0) goto fail;
	// 		// if (c1[b[i]] + min2 < 0) goto fail;
	// 	} else {
	// 		if (-min1 > min2 + c[i]) goto fail;
	// 	}
	// }

	goto success;

	// printf("%lld\n", result);
	// printf("%.15lf\n", dresult);
	// puts(s);

	return 0;

	success:
	// puts("YES");
	puts("Yes");
	// printf("%llu\n", result);
	// puts("0");
	// puts("Yay!");
	return 0;

	fail:
	// puts("NO");
	puts("No");
	// puts("0");
	// puts("-1");
	// puts("-1 -1 -1");
	// puts("Impossible");
	return 1;
}

int32_t main (void) {
	int32_t i, j;
	int32_t x, y;



	scanf("%llu%llu", &h, &w);
	scanf("%llu", &n, &m);
	// scanf("%llu", &k, &n, &m);
	// scanf("%llu%llu", &h, &w);
	// scanf("%lld%lld", &va, &vb, &vc, &vd);
	// scanf("%llu%llu", &ua, &ub, &uc, &ud);
	// scanf("%llu", &q);
	// scanf("%s", s);
	// scanf("%s", t);
	for (i = 0; i < n; i++) {
		// scanf("%lld%lld", &xy[i].a, &xy[i].b);
		// scanf("%lld%lld%lld", &tup[i].a, &tup[i].b, &tup[i].c);
		scanf("%lld", &a[i]);
		scanf("%lld", &b[i]);
		scanf("%lld", &c[i]);
		// scanf("%lld", &d[i]);
		a[i]--;
		b[i]--;
		// c[i]--;
		// tup[i].a--;
		// tup[i].b--;
	}
	// scanf("%llu", &m, &k);
	// scanf("%llu", &q);
	// scanf("%s", s);
	// for (i = 0; i < m; i++) {
	// 	scanf("%lld", &b[i]);
	// 	// b[i]--;
	// }

	// for (i = 0; i < h; i++) {
	// 	for (j = 0; j < w; j++) {
	// 		scanf("%llu", &table[i][j]);
	// 	}
	// }
	// for (i = 0; i < h; i++) {
	// 	scanf("%s", &s[i]);
	// }

	solve();

	return 0;
}


Measured memory_bytes: 38840