#include <bits/stdc++.h>
using namespace std;
const int nmax = 1e5 + 1;
struct str {
int a, b, val;
const bool operator < (str ult) const {
return val < ult.val;
}
} v[nmax];
int aint[4 * nmax], lz[4 * nmax], fp[nmax], lp[nmax], fin[nmax];
vector<vector<int>> place;
void lazy(int nod, int st, int dr) {
aint[nod] = lz[nod];
if(st != dr) {
lz[nod << 1] = lz[nod];
lz[nod << 1|1] = lz[nod];
}
lz[nod] = 0;
}
void update(int nod, int st, int dr, int l, int r, int val) {
if(lz[nod]) {
lazy(nod, st, dr);
}
if(st > r || dr < l) {
return;
}
if(l <= st && dr <= r) {
lz[nod] = val;
lazy(nod, st, dr);
return;
}
int mid = (st + dr) / 2;
update(nod << 1, st, mid, l, r, val);
update(nod << 1|1, mid + 1, dr, l, r, val);
}
int query(int nod, int st, int dr, int poz) {
if(lz[nod]) {
lazy(nod, st, dr);
}
if(st == dr) {
return aint[nod];
}
int mid = (st + dr) / 2;
if(poz <= mid) {
return query(nod << 1, st, mid, poz);
} else {
return query(nod << 1|1, mid + 1, dr, poz);
}
}
int main() {
int n, q;
cin >> n >> q;
for(int i = 0; i <= n; i ++) {
fp[i] = 1, lp[i] = n;
}
for(int i = 1; i <= q; i ++) {
int a, b, val;
cin >> a >> b >> val;
a ++;
b ++;
v[i].a = a, v[i].b = b, v[i].val = val;
fp[val] = max(fp[val], a);
lp[val] = min(lp[val], b);
}
sort(v + 1, v + q + 1);
for(int i = 1; i <= q; i ++) {
update(1, 1, n, v[i].a, v[i].b, v[i].val);
}
place.resize(n + 1);
for(int i = 1; i <= n; i ++) {
int x = query(1, 1, n, i);
place[x].push_back(i);
}
set<int> curr;
for(int i = 0; i < n; i ++) {
for(auto it : place[i]) {
curr.insert(it);
}
auto poz = curr.lower_bound(fp[i]);
if(poz == curr.end() || (*poz) > lp[i]) {
for(int x = 1; x <= n; x ++) {
cout << "-1 ";
}
return 0;
}
fin[(*poz)] = i;
curr.erase(poz);
}
for(int i = 1; i <= n; i ++) {
cout << fin[i] << " ";
}
return 0;
}
