#include <bits/stdc++.h>
using namespace std;
int fat[105];
int n, m, x, y;
int maxf[105], id = 0;
int main()
{
cin >> n >> m;
while (m--)
{
cin >> x >> y;
fat[y] = x;
maxf[x]++;
if (maxf[id] < maxf[x])
id = x;
}
for (int i = 1; i <= n; i++)
if (fat[i] == 0)
{
cout << i << endl;
break;
}
cout << id << endl;
for (int i = 1; i <= n; i++)
if (fat[i] == id)
cout << i << " ";
return 0;
}