#include <fstream>
#include <vector>

using namespace std;

ifstream fin("sortaret.in");
ofstream fout("sortaret.out");

const int VAL=50005;

int N, M, i, j, A, B, K;
int SOL[VAL], grad[VAL], nod;
vector <int> G[VAL];
vector <int> :: iterator it;

int main()
{
    fin >> N >> M;
    for (i=1; i<=M; i++)
    {
        fin >> A >> B;
        G[A].push_back(B);
        grad[B]++;
    }
    for (i=1; i<=N; i++)
        if (grad[i]==0)
            SOL[++K]=i;
    while (1)
    {
        j++;
        if (j>N)
            break;
        if (j>K)
        {
            fout << "IMPOSIBIL";
            fin.close();
            fout.close();
            return 0;
        }
        nod=SOL[j];
        for (it=G[nod].begin(); it!=G[nod].end(); it++)
        {
            if (grad[*it]==0)
                continue;
            grad[*it]--;
            if (grad[*it]==0)
                SOL[++K]=*it;
        }
    }
    for (i=1; i<=N; i++)
        fout << SOL[i] << " ";
    fin.close();
    fout.close();
    return 0;
}