#include <bits/stdc++.h>

using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

const int INF=1e9;

int n,m,s,x,y;
vector<int> v[100005];
bool viz[100005];
int nr;

void dfs(int nod)
{
    viz[nod]=1;
    for (auto it:v[nod])
        if (viz[it]==0)
            dfs(it);
}

int main()
{
    f>>n>>m>>s;
    for (int i=1; i<=m; i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (int i=1;i<=n;i++)
        if (viz[i]==0)
            nr++,dfs(i);
    g<<nr;

    return 0;
}