#include <bits/stdc++.h> #include <atcoder/all> using namespace std; using namespace atcoder; using ll = long long; #define rep(i, n) for (int i=0; i<(int)(n); ++(i)) #define rep3(i, m, n) for (int i=(m); (i)<(int)(n); ++(i)) #define repr(i, n) for (int i=(int)(n)-1; (i)>=0; --(i)) #define rep3r(i, m, n) for (int i=(int)(n)-1; (i)>=(int)(m); --(i)) #define all(x) (x).begin(), (x).end() const int INF = (int)(2e9); int op(int l, int r) { return max(l, r); } int e() { return 1; } int mapping(int f, int r) { return max(f, r); } int composition(int f, int g) { return max(f, g); } int id() { return 1; } int op2(int l, int r) { return min(l, r); } int e2() { return INF; } int mapping2(int f, int r) { return min(f, r); } int composition2(int f, int g) { return min(f, g); } int id2() { return INF; } int main() { int n, q; cin >> n >> q; vector<int> l(q), r(q), b(q); rep(i, q) { cin >> l[i] >> r[i] >> b[i]; l[i]--; } lazy_segtree<int, op, e, int, mapping, composition, id> lseg1(n+1); rep(i, q) lseg1.apply(l[i], r[i], b[i]); vector<int> res(n); rep(i, n) res[i] = lseg1.get(i); lazy_segtree<int, op2, e2, int, mapping2, composition2, id2> lseg2(res); bool ok = true; rep(i, q) if (lseg2.prod(l[i], r[i]) != b[i]) ok = false; if (ok) rep(i, n) printf("%d%c", res[i], (i<n-1?' ':'\n')); else cout << -1 << endl; return 0; }