#include <bits/stdc++.h>
using namespace std;
struct W {
  int t, l, r;
} w[100010];
int n, m, s, f;
int main() {
  while (cin >> n >> m >> s >> f) {
    for (int i = (0); i < (m); i++) {
      cin >> w[i].t >> w[i].l >> w[i].r;
    }
    int t = 1, p = 0;
    int dir = f > s ? 1 : -1;
    while (s != f) {
      if (p < m && w[p].t == t &&
          ((w[p].l <= s && s <= w[p].r) ||
           (w[p].l <= s + dir && s + dir <= w[p].r))) {
        cout << "X";
      } else {
        s += dir;
        cout << (dir == 1 ? 'R' : 'L');
      }
      if (++t > w[p].t) p++;
    }
    cout << endl;
  }
  return 0;
}
