#include <bits/stdc++.h>
using namespace std;
#define int long long
#define all(a) (a).begin(),(a).end()
#define rep(i, n) for(int i = 0; i < (n); i++)
const int mod = 1000000007;
signed main(){
int n, m;
cin >> n >> m;
vector<int> l(m), r(m), w(m);
for (int i = 0; i < m; i++) {
cin >> l[i] >> r[i] >> w[i];
}
vector<int> v;
for (int i = 0; i < n; i++) v.push_back(i);
do {
bool ok = true;
for (int i = 0; i < m; i++) {
int mn = 1e18;
for (int j = l[i]; j <= r[i]; j++) {
mn = min(mn, v[j]);
}
if (mn != w[i]) {
ok = false;
break;
}
}
if (ok) {
for (int x : v) cout << x << ' ';
return 0;
}
} while(next_permutation(v.begin(), v.end()));
for (int i = 0; i < n; i++) cout << "-1 ";
return 0;
}
