#include<bits/stdc++.h>
using namespace std;
#define file "a"
// #define int long long
#define ll long long
#define pii pair<int, int>
#define pli pair<ll, int>
#define fi first
#define se second
#define sz(a) (int)a.size()
#define pb push_back
#define mask(i) (1 << i)
const int N = 1e5, inf = 1e9;
mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());
int rad(int l, int r) { return l + rd() % (r - l + 1); }
void MAX(int &a, int b) { a = max(a, b); }
void MIN(int &a, int b) { a = min(a, b); }
struct stt
{
int l, r, id;
bool operator < (const stt &o) const
{
return id > o.id;
}
};
int n, q;
int kq[N + 2], t[4 * N + 2], lim[N + 2], lz[4 * N + 2];
stt a[N + 2];
vector<pii> g[N + 2];
void down(int id)
{
if (lz[id] != 0)
{
MAX(t[id * 2], lz[id]);
MAX(t[id * 2 + 1], lz[id]);
MAX(lz[id * 2], lz[id]);
MAX(lz[id * 2 + 1], lz[id]);
lz[id] = 0;
}
}
void update(int l, int r, int id, int u, int v, int x)
{
if (r < u || v < l) return;
if (u <= l && r <= v)
{
MAX(t[id], x);
MAX(lz[id], x);
return;
}
down(id);
int m = (l + r) / 2;
update(l, m, id * 2, u, v, x);
update(m + 1, r, id * 2 + 1, u, v, x);
}
int get(int l, int r, int id, int u)
{
if (l == r) return t[id];
down(id);
int m = (l + r) / 2;
if (u <= m) return get(l, m, id * 2, u);
else return get(m + 1, r, id * 2 + 1, u);
}
void shutdown()
{
for (int i = 0; i < n; i++) cout << -1 << " ";
}
bool cmp(int a, int b)
{
return lim[a] < lim[b];
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (fopen(file".inp", "r"))
{
freopen(file".inp", "r", stdin);
freopen(file".out", "w", stdout);
}
cin >> n >> q;
memset(kq, -1, sizeof kq);
for (int i = 1; i <= q; i++)
{
int l, r, id;
cin >> l >> r >> id;
g[id].pb({l, r});
update(0, n - 1, 1, l, r, id);
}
for (int i = 0; i < n; i++) lim[i] = get(0, n - 1, 1, i);
set<int> st;
for (int i = 0; i < n; i++) st.insert(i);
vector<int> a1, a2;
for (int i = n - 1; i >= 0; i--)
{
if (sz(g[i]) == 0) { a2.pb(i); continue; }
int L = g[i][0].fi, R = g[i][0].se;
for (int j = 1; j < sz(g[i]); j++)
{
int l = g[i][j].fi, r = g[i][j].se;
if (R < l || r < L) { L = -1; break; }
MAX(L, l);
MIN(R, r);
}
if (L != -1)
{
set<int> :: iterator it;
it = st.lower_bound(L);
if (it == st.end() || *it > R) return shutdown(), 0;
kq[*it] = i;
}
for (pii x : g[i])
{
L = x.fi; R = x.se;
set<int> :: iterator it;
it = st.lower_bound(L);
vector<set<int> :: iterator> del;
while (it != st.end())
{
if (*it > R) break;
del.pb(it);
it++;
}
for (set<int> :: iterator x : del) st.erase(x);
}
}
for (int i = 0; i < n; i++) if (kq[i] == -1) a1.pb(i);
sort(a1.begin(), a1.end(), cmp);
sort(a2.begin(), a2.end());
for (int i = 0; i < sz(a1); i++)
{
if (lim[a1[i]] > a2[i]) return shutdown(), 0;
kq[a1[i]] = a2[i];
}
for (int i = 0; i < n; i++) cout << kq[i] << " ";
}
