#include <bits/stdc++.h>
using namespace std;
const int N = 3e3 + 1;
struct node {
  int w, x, y, z;
};
queue<int> q;
vector<int> g[N], rg[N];
int d[N][N], rd[N][N], vis[N];
vector<pair<int, int>> fg[N], frg[N];
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = 1; i <= m; i++) {
    int u, v;
    cin >> u >> v;
    g[u].push_back(v);
    rg[v].push_back(u);
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      vis[j] = 0;
      d[i][j] = n + 1;
    }
    vis[i] = 1;
    q.push(i);
    d[i][i] = 0;
    while (!q.empty()) {
      int v = q.front();
      q.pop();
      for (auto u : g[v]) {
        if (vis[u]) continue;
        vis[u] = 1;
        q.push(u);
        d[i][u] = d[i][v] + 1;
      }
    }
    for (int j = 1; j <= n; j++) {
      if (j == i) continue;
      if (d[i][j] != n + 1) fg[i].push_back({d[i][j], j});
    }
    sort(fg[i].begin(), fg[i].end());
    for (int j = 1; j <= n; j++) {
      vis[j] = 0;
      rd[i][j] = n + 1;
    }
    vis[i] = 1;
    q.push(i);
    rd[i][i] = 0;
    while (!q.empty()) {
      int v = q.front();
      q.pop();
      for (auto u : rg[v]) {
        if (vis[u]) continue;
        vis[u] = 1;
        q.push(u);
        rd[i][u] = rd[i][v] + 1;
      }
    }
    for (int j = 1; j <= n; j++) {
      if (j == i) continue;
      if (rd[i][j] != n + 1) frg[i].push_back({rd[i][j], j});
    }
    sort(frg[i].begin(), frg[i].end());
  }
  int ans = 0;
  node A;
  for (int b = 1; b <= n; b++) {
    for (int c = 1; c <= n; c++) {
      if (b == c || d[b][c] == n + 1) continue;
      int ans1 = 0, z = 0;
      node B;
      int sz1 = frg[b].size(), sz2 = fg[c].size();
      for (int j = sz1 - 1; j >= max(z, sz1 - 3); j--) {
        int a = frg[b][j].second;
        for (int k = sz2 - 1; k >= max(z, sz2 - 3); k--) {
          int dd = fg[c][k].second;
          if (a == c || dd == b || a == dd) continue;
          int ans2 = d[b][c] + rd[b][a] + d[c][dd];
          node C;
          C.w = a;
          C.x = b;
          C.y = c;
          C.z = dd;
          if (ans2 > ans1) {
            ans1 = ans2;
            B = C;
          }
        }
      }
      if (ans1 > ans) {
        ans = ans1;
        A = B;
      }
    }
  }
  cout << A.w << " " << A.x << " " << A.y << " " << A.z << "\n";
  return 0;
}
