using namespace std;
#include <iostream>
#include <vector>
#include <algorithm>
int main()
{
    int p, e, s;
    int a, b;
    cin >> p >> e >> s;
    vector<vector<int>> graf(p + 1);
    vector<vector<int>> farg(p + 1);
    for (int i = 0; i < e; i++)
    {
        cin >> a >> b;
        graf[a].push_back(b);
        farg[b].push_back(a);
    }
    int curr = s;
    vector<bool> vis(p);
    vector<int> st;
    vector<int> glhf;
    int n = 0;
    while (true)
    {
        vis[curr] = true;
        for (int i = 0; i < graf[curr].size(); i++)
        {
            if (graf[curr][i] != s && glhf.end() == find(glhf.begin(), glhf.end(), graf[curr][i]))
            {
                glhf.push_back(graf[curr][i]);
            }
        }
        for (int i = 0; i < farg[curr].size(); i++)
        {
            if (find(st.begin(), st.end(), farg[curr][i]) == st.end() && !vis[farg[curr][i]])
            {
                st.push_back(farg[curr][i]);
            }
        }
        if (n < st.size())
        {
            curr = st[n];
            n++;
        }
        else
        {
            break;
        }
    }
    cout << glhf.size() << endl;
    for (int i = 0; i < glhf.size(); i++)
    {
        cout << glhf[i] << " ";
    }
}