#include <bits/stdc++.h>
using namespace std;
int const N = 1000000;
int const B = 20;
int n, m;
bool valid;
int ans[N];
int cnt;
int maxc[N + 1], maxl[N + 1];
int minr[N + 1];
int st[B][N + 1];
int query(int l, int r) {
  int sz = r - l + 1;
  int b = 0;
  while ((1 << (b + 1)) < sz) {
    ++b;
  }
  return maxc[st[b][l]] > maxc[st[b][r - (1 << b) + 1]]
             ? st[b][l]
             : st[b][r - (1 << b) + 1];
}
void readin() {
  int u, v;
  char b[10];
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; ++i) {
    maxc[i] = i;
    maxl[i] = 0;
    minr[i] = INT_MAX;
  }
  valid = true;
  for (int i = 0; i < m; ++i) {
    scanf("%d%d%s", &u, &v, b);
    if (v <= u) {
      valid = false;
    }
    maxc[u] = max(maxc[u], v);
    if (b[0] == 'L') {
      maxl[u] = max(maxl[u], v);
    } else {
      minr[u] = min(minr[u], v);
    }
  }
}
bool build(int root, int limit) {
  if (root > limit) {
    return true;
  }
  int l_max = 0, r_min = minr[root];
  if (maxl[root] > root) {
    l_max = maxc[query(root + 1, maxl[root])];
  }
  if (l_max == 0) {
    ans[cnt++] = root;
    return build(root + 1, limit);
  } else if (r_min == INT_MAX) {
    bool ret = build(root + 1, limit);
    ans[cnt++] = root;
    return ret;
  } else {
    if (l_max >= r_min) {
      return false;
    }
    bool ret = true;
    ret = ret && build(root + 1, l_max);
    ans[cnt++] = root;
    ret = ret && build(l_max + 1, limit);
    return ret;
  }
}
void solve() {
  if (!valid) {
    printf("IMPOSSIBLE\n");
    return;
  }
  for (int i = n; i >= 1; --i) {
    if (maxc[i] > i) {
      maxc[i] = maxc[query(i + 1, maxc[i])];
    }
    st[0][i] = maxc[i];
    for (int b = 1; i + (1 << b) - 1 <= n; ++b) {
      st[b][i] = maxc[st[b - 1][i]] >= maxc[st[b - 1][i + (1 << (b - 1))]]
                     ? st[b - 1][i]
                     : st[b - 1][i + (1 << (b - 1))];
    }
  }
  cnt = 0;
  if (build(1, n)) {
    for (int i = 0; i < n; ++i) {
      printf("%d%c", ans[i], i < n - 1 ? ' ' : '\n');
    }
  } else {
    printf("IMPOSSIBLE\n");
  }
}
int main() {
  readin();
  solve();
  return 0;
}
