#include <fstream>
#include <vector>
#include <queue>
#pragma GCC optimize ("Ofast")

using namespace std;

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

int n, m, s;
vector <int> v[100005];
queue <int> q;
int x, y;
int used[100005];

void dfs(int nod)
{
    used[nod]=1;
    for(int i : v[nod])
        if(used[i]==0)
        dfs(i);
}

int main()
{
    fin>>n>>m>>s;
    for(int i=1; i<=m; i++)
    {
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    int ans = 0;
    for(int i=1; i<=n; i++)
        if(used[i]==0)
    {
        ans++;
        dfs(i);
    }
    fout<<ans;
    return 0;
}