#include <iostream>
#include<fstream>
#include<vector>
#include<queue>
#define N 100005


using namespace std;

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

queue<int> q;
class Graph {
private:
    int n, m;

    vector<int> adlist[N];
    bool viz[N] = {0};
    int dist[N] = {0};
public:
    void readDirected();
    void readUndirected();
    Graph(int n, int m):n(n), m(m){}

    void bfs(int first);
    void dfs(int first);

    void printDist();
    void connectedComponents();

};


void Graph::readDirected()
{
    int i, x, y;
    for(i = 1; i <= m; ++i)
    {
        fin >> x >> y;
        adlist[x].push_back(y);

    }
}

void Graph::readUndirected() {
    int i, x, y;
    for(i = 1; i <= m; ++i)
    {
        fin >> x >> y;
        adlist[x].push_back(y);
        adlist[y].push_back(x);

    }
}

void Graph::bfs(int first){
    int node, i, dim;
    dist[first] = 1;
    viz[first] = 1;
    q.push(first);

    while(!q.empty())
    {
        node = q.front();
        q.pop();
        dim = adlist[node].size();
        for(i = 0; i < dim; ++i)
            if(!viz[adlist[node][i]])
        {
            cout << adlist[node][i] <<" ";
            viz[adlist[node][i]] = 1;
            dist[adlist[node][i]] = dist[node] + 1;
            q.push(adlist[node][i]);
        }
    }
}
void Graph::dfs(int node){
    int i, dim;
    viz[node] = 1;
    dim = adlist[node].size();
    for(i = 0; i < dim; ++i)
            if(!viz[adlist[node][i]])
                dfs(adlist[node][i]);
}

void Graph::printDist()
{
    int i;
    for(i = 1; i <= n; ++i)
        fout << dist[i] - 1 << " ";
}
void Graph::connectedComponents() {
    int i, nr = 0;
    for(i = 1; i <= n; ++i)
        if(!viz[i])
    {
        nr++;
        dfs(i);
    }
    fout << nr;

}
int main()
{
    int i, first, n, m;

    fin >> n >> m >> first;
    Graph g(n, m);

    /*
    g.readOriented();
    g.bfs(first);
    g.printDist();
*/
    g.readUndirected();
    g.connectedComponents();

    return 0;
}