#include <fstream>
#include <vector>
#include <bitset>
using namespace std;

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

int n,m,s;
const int N=1e5;
vector<vector<int>>g;
bitset<N+1>viz;

void citire()
{
    fin>>n>>m>>s;
    int x,y;
    g.resize(n+1);
    for(int i=0; i<m; i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
}
void dfs(int nod)
{
    viz[nod]=1;
    for(auto x:g[nod])
        if(!viz[x])
            dfs(x);
}
int main()
{
    citire();
    int cnt=0;
    for (int i=1;i<=n;i++)
        if (!viz[i]) {
            cnt++;
            dfs(i);
        }
    fout<<cnt;
    return 0;
}