#include <bits/stdc++.h>

using namespace std;

ifstream f("sortaret.in");
ofstream g("sortaret.out");

vector <vector <int>> v;
stack <int> s;
int viz[50010];

void DFS(int node) {
    viz[node] = 1;
    for(int i = 0; i < v[node].size(); i++) {
        if(viz[v[node][i]] == 0) {
            DFS(v[node][i]);
        }
    }
    s.push(node);
}

int main()
{
    int n, m;
    f >> n >> m;
    v.resize(n + 1);
    for(int i = 0 ; i < n; i++) {
        int x, y;
        f >> x >> y;
        v[x].push_back(y);
    }
    DFS(1);
    while(!s.empty()) {
        int x = s.top();
        s.pop();
        g << x << " ";
    }
    return 0;
}