#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;

const int NMAX =100001;
vector<int> G[NMAX];
vector<int> viz;
int cc;

void dfs(int v);

int main()
{

    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);


    int n,m;
    int u,v;
    int i;

    scanf("%d%d",&n,&m);

    for(i=1; i<=n; ++i)
    {
        scanf("%d%d",&u,&v);
        G[u].push_back(v);
        G[v].push_back(u);
    }

    viz.assign(n+1,0);

    for(i=1; i<=n; ++i)
        if(!viz[i])
        {
            ++cc;
            dfs(i);
        }


    printf("%d\n",cc);
    return 0;
}

void dfs(int u)
{
    viz[u]=cc;
    for(int j=0; j<(int)G[u].size(); ++j)
    {
        int v=G[u][j];
        if(!viz[v])
            dfs(v);
    }
}