#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("sortaret.in");
ofstream fout("sortaret.out");

int n, m;
vector<int> gr[50005];

void citire() {
  fin >> n >> m;
  for (int i = 1; i <= m; i++) {
    int x, y;
    fin >> x >> y;
    gr[x].push_back(y);
  }
}

void parcComp() {
  for (int i = 1; i <= n; i++) {
    if (gr[i].size() != 0) {
      fout << i << " ";
      for (int j = 0; j < gr[i].size(); j++) {
        fout << gr[i][j] << " ";
        gr[gr[i][j]].clear();
      }
    }
  }
}

int main(int argc, const char * argv[]) {
  citire();
  parcComp();
}