#include <bits/stdc++.h>
using namespace std;

#define int long long

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x),end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<pair<int, int>> vpii;

template<class T> using vec = vector<T>;
template<class T> using uset = unordered_set<T>;
template<class K, class V> using umap = unordered_map<K, V>;

void solve() {
    int N, M;

    cin >> N >> M;

    multimap<int, pii> grooves;

    multimap<int, int> hunters;

    rep(i, 1, N+1) {
        hunters.emplace(i, i);
    }

    rep(i, 0, M) {
        int xp, yp, xq, yq;

        cin >> xp >> yp >> xq >> yq;

        grooves.emplace(yp, make_pair(xp, xq));
    }

    for (auto [yp, groove_x] : grooves) {
        auto [xp, xq] = groove_x;
        auto groove_hunter_it = hunters.find(xp);

        vec<pii> to_emplace;

        while ((groove_hunter_it = hunters.find(xp)) != hunters.end()) {
            auto hunter_pair = *groove_hunter_it;
            to_emplace.emplace_back(xq, hunter_pair.second);
            hunters.erase(groove_hunter_it);
        }

        while ((groove_hunter_it = hunters.find(xq)) != hunters.end()) {
            auto hunter_pair = *groove_hunter_it;
            to_emplace.emplace_back(xp, hunter_pair.second);
            hunters.erase(groove_hunter_it);
        }

        for (auto [xq, hunter_i]: to_emplace) {
            hunters.emplace(xq, hunter_i);
        }
    }

    vi res(N+1, -1);

    for (auto hunter_pair : hunters ) {
        res[hunter_pair.second] = hunter_pair.first;
    }

    rep(i, 1, N+1) {
        cout << res[i] << '\n';
    }
}

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    ll T = 1;
    // cin >> T;
    rep(i, 0, T) solve();
}