#include <bits/stdc++.h>
//#include "bits_stdc++.h"
#define f first
#define s second
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define show(x) cerr << #x << " is " << x << endl;
#define show2(x,y) cerr << #x << " is " << x << " " << #y << " is " << y << endl;
#define show3(x,y,z) cerr << #x << " is " << x << " " << #y << " is " << y << " " << #z << " is " << z << endl;
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pi;
ll const INF = 1e9;
ll n,q;
ll minl ,maxl, minr, maxr;
vector<vector<pi> >queries;
vector<vector<ll> > newq;
vector<ll> ans;
struct node{
int s, e, m; //range is [s,e], m is the middle point
ll val, pos; //sum of [s,e]
ll lazy; //lazy tag of [s,e]
node *l, *r; //create two children l and r, where l is [s,m] and [m+1,e]
node (int S, int E){ //constructor called node
s = S, e = E, m = (s+e)/2;
val = 0;
pos = s;//initially all values are 0
lazy = 0; //lazy tag of 0 will mean there is no update (sentinel value)
l=r=nullptr;
}
void create()
{
if(s != e && l==nullptr){ //node is not yet a leaf, so create two children
l = new node(s, m); //create left child
r = new node(m+1, e); //create right child
}
}
void propogate(){
if (lazy==0) return; //nothing happens
create();
val+=lazy; //(e-s+1) is the length of the range
if (s != e){ //not a leaf, send lazy tags to children
l->lazy+=lazy;
r->lazy+=lazy;
}
lazy=0; //set our lazy tag value back to the sentinel
}
void update(int S, int E, ll V){ //increment [S,E] by V
propogate();
if(s==S && e==E) lazy += V; //update covers range, update lazy tag
else{ //go we have to go deeper
create();
if(E <= m) l->update(S, E, V); //[S,E] is in the left child
else if (m < S) r->update(S, E, V); //[S,E] is in the right child
else l->update(S, m, V),r->update(m+1, E, V);
l->propogate(),r->propogate();
//remember to propogate your children before update yourself
if (l->val<=r->val) {val = l->val, pos = l-> pos;}
else {val = r->val, pos = r-> pos;}
}
}
pi query(int S, int E){
propogate(); //remember to propogate
if(s == S && e == E) {return mp(val, pos); }//case 1
create();
if(E <= m) {return l->query(S, E);} //case 2, recurse to left child
else if(S >= m+1) {return r->query(S, E);} //case 3, recurse to right child
else //case 4, split the query range, recurse to both childs
{
pi a = l->query(S, m), b = r->query(m+1, E);
if (a.f<=b.f) return a;
else return b;
}
}
} *root;
void merge(pi a)
{
minl = min(minl, a.f);
maxl = max(maxl, a.f);
minr = min(minr, a.s);
maxr = max(maxr, a.s);
}
void end()
{
while (n--) cout << -1 << ' ';
}
int main()
{
cin >> n >> q;
queries.resize(n);
newq.resize(n);
ans.resize(n);
for (ll i=0; i<q; ++i)
{
ll a, b ,c;
cin >> a >> b >> c;
queries[c].pb(mp(a,b));
}
root = new node(0, n-1);
for (ll i=n-1; i>=0; --i)
{
if (!queries[i].empty())
{
minl=INF, maxl = -1, minr= INF, maxr = -1;
for (pi u: queries[i]) merge(u);
//show3(minl, maxl, minr);
//show(maxr);
if (maxl>minr) {end(); return 0;}
root->update(minl, maxr, 1);
newq[i].pb(minl);
newq[i].pb(maxl);
newq[i].pb(minr);
newq[i].pb(maxr);
}
}
for (ll i=0; i<n; ++i)
{
if (!newq[i].empty())
{
root->update(newq[i][0], newq[i][3], -1);
pi ret = root->query(newq[i][1], newq[i][2]);
if (ret.f>0) {end(); return 0;}
root->update(ret.s, ret.s, INF);
ans[ret.s] = i;
}
else
{
pi ret = root->query(0, n-1);
if (ret.f>0) {end(); return 0;}
root->update(ret.s, ret.s, INF);
ans[ret.s] = i;
}
}
for (ll u: ans) cout << u << ' ';
return 0;
}
