#include <iostream>

using namespace std;

int a[101][101], n, m, i, j, c = 0, ok = 0;
void citgr();
int main()
{
    citgr();
    for ( j = 1; j <= n; j++ )
        for ( i = 1; i <= n; i++ )
        a[0][j] += a[i][j];
    for ( i = 1; i <= n; i++ )
        {
            if ( a[0][i] == 0 )
              {
                ok = 1;
                cout<< i << " ";
              }
        }
        if ( ok == 0 )
            cout << "NU EXISTA";

return 0;
}
void citgr()
{
    cin >> n >> m;
    int x, y;
    for ( i = 1; i <= m; i++ )
    {
        cin >> x >> y;
        a[x][y] = 1;
    }

}