#include<bits/stdc++.h>
#define LL long long
#define LD long double
#define ull unsigned long long
#define fi first
#define se second
#define mk make_pair
#define PLL pair<LL, LL>
#define PLI pair<LL, int>
#define PII pair<int, int>
#define SZ(x) ((int)x.size())
#define ALL(x) (x).begin(), (x).end()
#define fio ios::sync_with_stdio(false); cin.tie(0);
using namespace std;const int N = 1e6 + 7;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;
const double eps = 1e-8;
const double PI = acos(-1);template<class T, class S> inline void add(T& a, S b) {a += b; if(a >= mod) a -= mod;}
template<class T, class S> inline void sub(T& a, S b) {a -= b; if(a < 0) a += mod;}
template<class T, class S> inline bool chkmax(T& a, S b) {return a < b ? a = b, true : false;}
template<class T, class S> inline bool chkmin(T& a, S b) {return a > b ? a = b, true : false;}struct Bit {int a[N];void modify(int x, int v) {for(int i = x; i < N; i += i & -i)a[i] += v;}int sum(int x) {int ans = 0;for(int i = x; i; i -= i & -i)ans += a[i];return ans;}
};int n, m;
char s[10];
vector<PII> vc[N];
vector<int> ans;
Bit bit;void dfs(int l, int r) {if(l > r) return;if(l == r) {ans.push_back(l);return;}int L = l, R = r;for(auto& t : vc[l]) {if(t.se) chkmin(R, t.fi - 1);else chkmax(L, t.fi);bit.modify(l, -1);bit.modify(t.fi, 1);}for( ; L <= R; L++, R--) {if(!bit.sum(L)) {dfs(l + 1, L);ans.push_back(l);dfs(L + 1, r);return;}if(!bit.sum(R)) {dfs(l + 1,  R);ans.push_back(l);dfs(R + 1, r);return;}}puts("IMPOSSIBLE");exit(0);
}int main() {scanf("%d%d", &n, &m);for(int i = 1; i <= m; i++) {int a, b;scanf("%d%d%s", &a, &b, s);if(b <= a) {puts("IMPOSSIBLE");return 0;}if(s[0] == 'L') vc[a].push_back(mk(b, 0));else vc[a].push_back(mk(b, 1));bit.modify(a, 1);bit.modify(b, -1);}dfs(1, n);for(auto& t : ans) printf("%d ", t);puts("");return 0;
}/*
*/