#include <bits/stdc++.h>
using namespace std;
struct node {
  int val, num;
} to[3001][4], from[3001][4];
const int MMAX = 0x7ffffff;
int n, e;
vector<int> v[3001];
int dist[3001][3001];
bool judge[3001][3001];
bool visited[3001];
void bfs(int start) {
  memset(visited, false, sizeof(visited));
  visited[start] = true;
  queue<int> q;
  dist[start][start] = 0;
  int i, x;
  q.push(start);
  while (!q.empty()) {
    x = q.front();
    q.pop();
    for (i = 0; i < v[x].size(); i++)
      if (!visited[v[x][i]]) {
        visited[v[x][i]] = true;
        dist[start][v[x][i]] = dist[start][x] + 1;
        q.push(v[x][i]);
      }
  }
}
int main() {
  int i, j, k, t, x, y, ans = -1, a, b, c, d;
  scanf("%d%d", &n, &e);
  for (i = 1; i <= e; i++) {
    scanf("%d%d", &x, &y);
    if (x == y || judge[x][y]) continue;
    v[x].push_back(y);
    judge[x][y] = true;
  }
  for (i = 1; i <= n; i++)
    for (j = 1; j <= n; j++) dist[i][j] = -MMAX;
  for (i = 1; i <= n; i++) bfs(i);
  for (i = 1; i <= n; i++) {
    from[i][1].val = from[i][2].val = from[i][3].val = -MMAX - 1;
    to[i][1].val = to[i][2].val = to[i][3].val = -MMAX - 1;
  }
  for (i = 1; i <= n; i++)
    for (j = 1; j <= n; j++) {
      if (i == j) continue;
      for (k = 1; k <= 3; k++)
        if (to[i][k].val < dist[i][j]) break;
      if (k <= 3) {
        for (t = 3; t >= k + 1; t--) to[i][t] = to[i][t - 1];
        to[i][k].val = dist[i][j];
        to[i][k].num = j;
      }
      for (k = 1; k <= 3; k++)
        if (from[i][k].val < dist[j][i]) break;
      if (k <= 3) {
        for (t = 3; t >= k + 1; t--) from[i][t] = from[i][t - 1];
        from[i][k].val = dist[j][i];
        from[i][k].num = j;
      }
    }
  for (i = 1; i <= n; i++)
    for (j = 1; j <= n; j++)
      if (i != j && dist[i][j] > 0) {
        for (k = 1; k <= 3; k++)
          for (t = 1; t <= 3; t++)
            if (from[i][k].val > 0 && to[j][t].val > 0 &&
                from[i][k].num != to[j][t].num && from[i][k].num != j &&
                to[j][t].num != i &&
                from[i][k].val + dist[i][j] + to[j][t].val > ans) {
              ans = from[i][k].val + dist[i][j] + to[j][t].val;
              a = from[i][k].num;
              b = i;
              c = j;
              d = to[j][t].num;
            }
      }
  printf("%d %d %d %d\n", a, b, c, d);
  return 0;
}
