#include <bits/stdc++.h>
using namespace std;
const int N = 1234567;
int fenw[N];
void modify(int x, int v) {
  while (x < N) {
    fenw[x] += v;
    x = (x | (x - 1)) + 1;
  }
}
int find_sum(int x) {
  int v = 0;
  while (x > 0) {
    v += fenw[x];
    x &= x - 1;
  }
  return v;
}
int a[N], b[N], dir[N];
int k;
vector<int> ret;
vector<int> g[N];
void solve(int root, int to) {
  if (root > to) {
    return;
  }
  if (root == to) {
    ret.push_back(root);
    return;
  }
  int sz = g[root].size();
  int sfrom = root;
  int sto = to;
  for (int q = 0; q < sz; q++) {
    int j = g[root][q];
    if (dir[j] == 0) {
      if (b[j] > sfrom) {
        sfrom = b[j];
      }
    }
    if (dir[j] == 1) {
      if (b[j] - 1 < sto) {
        sto = b[j] - 1;
      }
    }
    modify(a[j], -1);
    modify(b[j], 1);
  }
  int parity = 0;
  while (sfrom <= sto) {
    if (parity) {
      if (find_sum(sfrom) == 0) {
        solve(root + 1, sfrom);
        ret.push_back(root);
        solve(sfrom + 1, to);
        return;
      }
      sfrom++;
    } else {
      if (find_sum(sto) == 0) {
        solve(root + 1, sto);
        ret.push_back(root);
        solve(sto + 1, to);
        return;
      }
      sto--;
    }
    parity ^= 1;
  }
  puts("IMPOSSIBLE");
  exit(0);
}
int main() {
  int n;
  scanf("%d %d", &n, &k);
  char foo[42];
  for (int i = 1; i <= n; i++) {
    fenw[i] = 0;
    g[i].clear();
  }
  for (int i = 0; i < k; i++) {
    scanf("%d %d %s", a + i, b + i, foo);
    if (a[i] < 1 || a[i] > n || b[i] < 1 || b[i] > n || b[i] <= a[i]) {
      puts("IMPOSSIBLE");
      return 0;
    }
    dir[i] = (foo[0] == 'L' ? 0 : 1);
    modify(a[i], 1);
    modify(b[i], -1);
    g[a[i]].push_back(i);
  }
  ret.clear();
  solve(1, n);
  for (int i = 0; i < n - 1; i++) {
    printf("%d ", ret[i]);
  }
  printf("%d\n", ret[n - 1]);
  return 0;
}
