#include <fstream>
#include <vector>

using namespace std;

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

int n, m, i, x, y;
vector<int>ls[50005];
bool viz[50005];
int stiva[50005], vf;

void dfs(int x) {
    int l = ls[x].size(), i, y;
    viz[x]=1;
    for (i = 0; i < l; i++) {
        y = ls[x][i];
        if (viz[y]==0)dfs(y);
    }
    stiva[++vf] = x;
}

int main() {
    f >> n >> m;
    for (i = 1; i <= n; i++) {
        f >> x >> y;
        ls[x].push_back(y);
    }
    dfs(1);
    for (i=vf;i;i--)
        g << stiva[i] << ' ';
    return 0;
}