// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define endl '\n';
#define fastio ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define py cout << "YES" << endl;
#define pn cout << "NO" << endl;
#define pb push_back
#define int long long
typedef long double lld;
#define double lld
typedef long long ll;
typedef unsigned long long ull;
const ll inf = 1e18;
const ll mod = 1e9+7;
const int N = 2e5;
vector<int>primes = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97};
// Check for queue, priorioty_queue, stack, ordered_set solutions
// stack => LIFO (whatever goes in last comes out last)
// queue => FIFO (whatever goes in first comes out first)
// priority_queue => Dynamic queries of minimum/maximum
// ordered_set => set in vector form
//[order_of_key(k) gives number of elements less than k, while find_by_order(i) gives i^th element]
// To comment multiple lines : ctrl + /
// To find and replace : ctrl+H
void judge(){
srand(time(NULL));
#ifndef ONLINE_JUDGE
freopen("1.txt","r",stdin);
freopen("2.txt","w",stdout);
freopen("Error.txt", "w", stderr);
#define debug(x...) cerr << #x <<" = "; _print(x); cerr << endl;
#else
#define debug(x...)
#endif
}
void usaco(string s) {
freopen((s + ".in").c_str(),"r",stdin);
freopen((s + ".out").c_str(),"w",stdout);
}
struct node {
int sum; // The sum of the range (used for sum queries)
node(int x = 0){
sum = x;
}
};
struct lazyNode {
bool is_set = false; // Flag for set operation
int set_val = inf; // Value for the set operation
int add_val = 0; // Value for the add operation
};
class LazySegmentTree {
private:
vector<node> t;
vector<lazyNode> lazy;
int n;
vector<int>a;
#define mid (start+end)/2
#define lc x + 1
#define rc 2*(mid-start+1)+x
node unite(node a, node b) {
return node(a.sum+b.sum);
}
void build(int x, int start, int end) {
if (start == end) {
t[x]= node(a[start]);
return;
}
build(lc, start, mid);
build(rc, mid + 1, end);
t[x] = unite(t[lc], t[rc]);
}
void push(int x, int start, int end) { // MAKE CHANGES HERE
if (lazy[x].is_set) {
t[x].sum = (end - start + 1) * lazy[x].set_val;
if (start != end) {
lazy[lc].is_set = true;
lazy[rc].is_set = true;
lazy[lc].set_val = lazy[rc].set_val = lazy[x].set_val;
lazy[lc].add_val = lazy[rc].add_val = 0;
}
lazy[x].is_set = false;
}
t[x].sum += (end - start + 1) * lazy[x].add_val;
if (start != end) {
lazy[lc].add_val += lazy[x].add_val;
lazy[rc].add_val += lazy[x].add_val;
}
lazy[x].add_val = 0;
}
void update(int x, int start, int end, int l, int r, int add_value) {
push(x, start, end);
if (l <= start && end <= r) {
if (add_value != 0) {
lazy[x].add_val += add_value;
}
push(x, start, end);
return;
}
if(r<=mid){
push(rc,mid+1,end);
update(lc,start,mid,l,r,add_value);
}
else if(mid<l){
push(lc,start,mid);
update(rc,mid+1,end,l,r,add_value);
}
else{
update(lc,start,mid,l,mid,add_value);
update(rc,mid+1,end,mid+1,r,add_value);
}
t[x] = unite(t[lc], t[rc]); // Update current node using unite
}
void set(int x, int start, int end, int l, int r, int set_value) {
push(x, start, end);
if (l <= start && end <=r) {
lazy[x].is_set = true;
lazy[x].set_val = set_value;
lazy[x].add_val = 0;
push(x, start, end);
return;
}
if(r<=mid){
push(rc,mid+1,end);
set(lc,start,mid,l,r,set_value);
}
else if(mid<l){
push(lc,start,mid);
set(rc,mid+1,end,l,r,set_value);
}
else{
set(lc,start,mid,l,mid,set_value);
set(rc,mid+1,end,mid+1,r,set_value);
}
t[x] = unite(t[lc], t[rc]);
}
node query(int x, int start, int end, int l, int r) {
push(x, start, end);
if (l <= start && end<=r) {
return t[x];
}
if(r<=mid){
return query(lc,start,mid,l,r);
}
else if(mid<l){
return query(rc,mid+1,end,l,r);
}
else{
return unite(query(lc,start,mid,l,r),query(rc,mid+1,end,l,r));
}
}
public:
LazySegmentTree(vector<int>&tmp) {
n = tmp.size();
a = tmp;
t.resize(2 * n);
lazy.resize(2 * n);
build(0, 0, n - 1); // Build the t using the input array
}
void update(int l, int r, int add_value) {
update(0, 0, n - 1, l, r, add_value);
}
void set(int l, int r, int set_value) {
set(0, 0, n - 1, l, r, set_value);
}
node query(int l, int r) {
node result = query(0, 0, n - 1, l, r);
return result; // Return only the sum from the queried node
}
};
void bad(int n){
for(int i = 0;i<n;i++){
cout << -1 << ' ';
}
}
signed main(){
fastio; //judge();
int n,q; cin >> n >> q;
vector<pair<int,int>>a(n,{-1,inf});
vector<vector<pair<int,int>>>all(n);
set<int>fs; set<int>others; set<int>fs2;
for(int i = 0;i<n;i++) others.insert(i);
while(q--){
int l,r,x; cin >> l >> r >> x;
all[x].pb({l,r});
a[x].first = max(a[x].first,l);
a[x].second = min(a[x].second,r);
fs.insert(x);
if(others.count(x)){
others.erase(others.find(x));
}
}
fs2 = fs;
// Put all the numbers in their "smaller" bound limits
vector<int>tmp(n,-1);
LazySegmentTree seg(tmp);
for(int i = 0;i<n;i++){
if(a[i].second<a[i].first){
bad(n); return 0;
}
if(a[i].first==-1){
continue;
}
seg.set(a[i].first,a[i].second,i);
}
for(int i = 0;i<n;i++){
tmp[i] = seg.query(i,i).sum;
}
vector<int>ans(n,-1);
for(int i = 0;i<n;i++){
if(tmp[i]==-1){
continue;
}
if(fs.count(tmp[i])){
ans[i] = tmp[i];
fs.erase(fs.find(tmp[i]));
}
}
if(fs.size()!=0){
bad(n); return 0;
}
fs = fs2;
// // Put the other numbers
// If there are restrictions
fill(tmp.begin(),tmp.end(),-1);
LazySegmentTree seg2(tmp);
for(int i = 0;i<n;i++){
for(auto [l,r]:all[i]){
seg2.set(l,r,i);
}
}
for(int i = 0;i<n;i++){
tmp[i] = seg2.query(i,i).sum;
if(fs.count(tmp[i])){
fs.erase(fs.find(tmp[i]));
}
}
if(fs.size()>0){
bad(n); return 0;
}
for(int i = 0;i<n;i++){
if(tmp[i]==-1 or ans[i]!=-1){
continue;
}
auto it = lower_bound(others.begin(),others.end(),tmp[i]);
if(it==others.end()){
bad(n); return 0;
}
ans[i] = *it;
others.erase(it);
}
// // If no restricitons left
for(int i = 0;i<n;i++){
if(ans[i]==-1){
if(others.size()==0){
bad(n); return 0;
}
auto it = others.begin();
ans[i] = *it;
others.erase(it);
}
}
for(auto x : ans) cout << x << ' ';
}
