#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, s, f, add = 0, rund = 1;
  cin >> n >> m >> s >> f;
  if (s < f)
    add = 1;
  else
    add = -1;
  for (int i = 0; i < m; i++) {
    int t, l, r;
    cin >> t >> l >> r;
    while (rund < t) {
      if (s == f) break;
      if (add == 1)
        cout << 'R';
      else if (add == -1)
        cout << 'L';
      s += add;
      rund++;
    }
    if (s == f) continue;
    if (t == rund) {
      rund++;
      if (s >= l && s <= r || s + add >= l && s + add <= r)
        cout << 'X';
      else if (add == 1) {
        cout << 'R';
        s += add;
      } else if (add == -1) {
        cout << 'L';
        s += add;
      }
    }
  }
  while (s != f) {
    if (add == 1)
      cout << 'R';
    else if (add == -1)
      cout << 'L';
    s += add;
  }
  cout << endl;
  return 0;
}
