#include <bits/stdc++.h>
using namespace std;
int const N = 1000000;
int n, m;
vector<vector<pair<int, int> > > adj;
bool valid;
int ans[N];
int cnt;
int st[N * 3];
void readin() {
  int u, v;
  char b[10];
  scanf("%d%d", &n, &m);
  valid = true;
  adj.clear();
  adj.resize(n + 1);
  for (int i = 0; i < m; ++i) {
    scanf("%d%d%s", &u, &v, b);
    if (v <= u) {
      valid = false;
    }
    adj[u].push_back(make_pair(v, b[0] == 'L' ? 0 : 1));
  }
}
inline int lc(int root) { return root << 1; }
inline int rc(int root) { return (root << 1) | 1; }
void init_st(int root, int l, int r) {
  if (l == r) {
    st[root] = l;
    return;
  }
  int mid = (l + r) >> 1;
  init_st(lc(root), l, mid);
  init_st(rc(root), mid + 1, r);
  st[root] = max(st[lc(root)], st[rc(root)]);
}
void update_st(int root, int l, int r, int x, int v) {
  if (l == r) {
    st[root] = v;
    return;
  }
  int mid = (l + r) >> 1;
  if (x <= mid) {
    update_st(lc(root), l, mid, x, v);
  } else {
    update_st(rc(root), mid + 1, r, x, v);
  }
}
int query_st(int root, int l, int r, int x, int y) {
  if (l == r) {
    return st[root];
  }
  int mid = (l + r) >> 1;
  if (y <= mid) {
    return query_st(lc(root), l, mid, x, y);
  } else if (x > mid) {
    return query_st(rc(root), mid + 1, r, x, y);
  } else {
    return max(query_st(lc(root), l, mid, x, mid),
               query_st(rc(root), mid + 1, r, mid + 1, y));
  }
}
bool build(int root, int limit) {
  if (root > limit) {
    return true;
  }
  int l_max = 0, r_min = INT_MAX;
  for (vector<pair<int, int> >::const_iterator it = adj[root].begin();
       it != adj[root].end(); ++it) {
    if (it->second == 0) {
      l_max = max(l_max, query_st(1, 1, n, root + 1, it->first));
    } else {
      r_min = min(r_min, it->first);
    }
  }
  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;
  }
  init_st(1, 1, n);
  for (int i = n; i >= 1; --i) {
    int u = i;
    for (vector<pair<int, int> >::const_iterator it = adj[i].begin();
         it != adj[i].end(); ++it) {
      u = max(u, it->first);
    }
    update_st(1, 1, n, i, query_st(1, 1, n, i, u));
  }
  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;
}
