#include <bits/stdc++.h>

using namespace std;

const int NMAX = 100002;

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

int N, M, V;

vector < int > Ad[NMAX];
queue < int > Q;

int x, y;
bool viz[NMAX];

void DFS( int nod )
{
    viz[nod] = 1;
    for( int i = 0; i < Ad[nod].size(); ++i )
    {
        int w = Ad[nod][i];

        if( !viz[w] ) DFS( w );
    }
}
void Read()
{
    fin >> N >> M >> V;

    for( int i = 1; i <= M; ++i )
    {
        fin >> x >> y;
        Ad[x].push_back( y );
        Ad[y].push_back( x );
    }

    int ct = 0;
    for( int i = 1; i <= N; ++i )
        if( viz[i] == 0 )
            {DFS( i );ct++;}
    fout << ct;
}
int main()
{
    Read();
    return 0;
}