#include <bits/stdc++.h>
using namespace std;
long long n, m, inf = 4e18, Lx, Ly, Rx, Ry;
struct str {
  long long x, y, w, k, t;
} s[2000005];
void Fail() {
  printf("NO");
  exit(0);
}
long long cmp(str a, str b) { return a.w < b.w; }
int main() {
  scanf("%lld%lld", &n, &m);
  s[n + 1].k = -1;
  s[n + 1].w = m;
  for (long long i = 1; i <= n; i++) {
    scanf("%lld%lld%lld", &s[i].t, &s[i].x, &s[i].y);
    long long x = s[i].x + s[i].y + s[i].t, y = s[i].y - s[i].x + s[i].t;
    if (x & 1 || y & 1) Fail();
    s[i].x = x / 2;
    s[i].y = y / 2;
  }
  long long Lx = -inf, Ly = -inf, Rx = inf, Ry = inf, flag = 0;
  for (long long i = 1; i <= n; i++) {
    s[i].w = s[i].t % m;
    s[i].k = s[i].t / m;
  }
  sort(s + 1, s + n + 1, cmp);
  for (long long i = 1; i <= n + 1; i++) {
    long long lx = s[i].x - s[i - 1].x - (s[i].w - s[i - 1].w),
              rx = s[i].x - s[i - 1].x, k = s[i].k - s[i - 1].k;
    long long ly = s[i].y - s[i - 1].y - (s[i].w - s[i - 1].w),
              ry = s[i].y - s[i - 1].y;
    if (!k) {
      if (lx > 0 || rx < 0 || ly > 0 || ry < 0) Fail();
    } else if (k > 0) {
      Lx = max(Lx, (long long)ceil(1.0L * lx / k));
      Rx = min(Rx, (long long)floor(1.0L * rx / k));
      Ly = max(Ly, (long long)ceil(1.0L * ly / k));
      Ry = min(Ry, (long long)floor(1.0L * ry / k));
    } else {
      Lx = max(Lx, (long long)ceil(1.0L * rx / k));
      Rx = min(Rx, (long long)floor(1.0L * lx / k));
      Ly = max(Ly, (long long)ceil(1.0L * ry / k));
      Ry = min(Ry, (long long)floor(1.0L * ly / k));
    }
  }
  if (Lx > Rx || Ly > Ry) Fail();
  for (long long i = 1; i <= n + 1; i++) {
    long long dx = (s[i].x - s[i].k * Lx) - (s[i - 1].x - s[i - 1].k * Lx);
    long long dy = (s[i].y - s[i].k * Ly) - (s[i - 1].y - s[i - 1].k * Ly);
    long long t = s[i].w - s[i - 1].w, x = 0, y = 0;
    while (t--) {
      if (x < dx) {
        ++x;
        if (y < dy)
          printf("U"), y++;
        else
          printf("R");
      } else {
        if (y < dy)
          printf("L"), y++;
        else
          printf("D");
      }
    }
  }
}
