#include <bits/stdc++.h>
#define NMAX 100010
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,x,y,x1,y1,nr,uz[NMAX];
vector <int> v[NMAX];
void citire()
{
    f>>n>>m>>x;
    for(int i=1; i<=m; ++i)
     {
         f>>x1>>y1;
         v[x1].push_back(y1);
         v[y1].push_back(x1);
     }
}
void dfs(int x)
{
    uz[x]=1;
    for(int i=0; i<v[x].size(); i++)
        if(uz[v[x][i]]==0)
            dfs(v[x][i]);
}
int main()
{
    citire();
    for(int i=1; i<=n; i++)
        if(uz[i]==0)
        {
            dfs(i);
            nr++;
        }
    g<<nr;
    return 0;
}