#include <bits/stdc++.h>
using namespace std;
struct Point {
  long long x, y;
  long long t;
} a[200005];
int n, l;
long long l1, r1, l2, r2;
bool cmp(Point a, Point b) { return a.t % l < b.t % l; }
int main() {
  scanf("%d%d", &n, &l);
  a[0].x = a[0].y = a[0].t = 0;
  for (int i = 1; i <= n; i++) {
    scanf("%lld%lld%lld", &a[i].t, &a[i].x, &a[i].y);
    if ((a[i].t - a[i].x - a[i].y) & 1) return puts("NO"), 0;
  }
  sort(a, a + n + 1, cmp);
  a[n + 1].t = -l;
  l1 = l2 = -1e18, r1 = r2 = 1e18;
  for (int i = 0; i <= n; i++) {
    long long d = a[i + 1].t / l - a[i].t / l;
    long long x = a[i + 1].x - a[i].x, y = a[i + 1].y - a[i].y;
    long long t = a[i + 1].t % l - a[i].t % l;
    if (i == n) t += l;
    long long a1 = x + y - t, b1 = x + y + t;
    long long a2 = x - y - t, b2 = x - y + t;
    if (d == 0 && (a1 > 0 || b1 < 0 || a2 > 0 || b2 < 0)) return puts("NO"), 0;
    if (d) {
      if (d < 0)
        d = -d, swap(a1, b1), swap(a2, b2), a1 = -a1, b1 = -b1, a2 = -a2,
        b2 = -b2;
      l1 = max(l1, a1 > 0 ? (a1 + d - 1) / d : a1 / d);
      r1 = min(r1, b1 > 0 ? b1 / d : (b1 - d + 1) / d);
      l2 = max(l2, a2 > 0 ? (a2 + d - 1) / d : a2 / d);
      r2 = min(r2, b2 > 0 ? b2 / d : (b2 - d + 1) / d);
    }
  }
  if (l1 > r1 || l2 > r2) return puts("NO"), 0;
  if ((l1 ^ l) & 1) {
    if (l1 == r1)
      return puts("NO"), 0;
    else
      l1++;
  }
  if ((l2 ^ l) & 1) {
    if (l2 == r2)
      return puts("NO"), 0;
    else
      l2++;
  }
  long long dx = (l1 + l2) / 2, dy = (l1 - l2) / 2;
  long long t = 0, x = 0, y = 0;
  for (int i = 1; i <= n; i++) {
    a[i].x -= a[i].t / l * dx;
    a[i].y -= a[i].t / l * dy;
    while (x < a[i].x) x++, t++, putchar('R');
    while (x > a[i].x) x--, t++, putchar('L');
    while (y < a[i].y) y++, t++, putchar('U');
    while (y > a[i].y) y--, t++, putchar('D');
    while (t < a[i].t % l) printf("LR"), t += 2;
  }
  while (x < dx) x++, t++, putchar('R');
  while (x > dx) x--, t++, putchar('L');
  while (y < dy) y++, t++, putchar('U');
  while (y > dy) y--, t++, putchar('D');
  while (t < l) printf("LR"), t += 2;
  printf("\n");
  return 0;
}
