#include <cstdio>
#include <vector>
#include <queue>

using namespace std;
const int nmax=100000;
vector<int> g[nmax+5];
vector<int> viz;
vector<int>::iterator it;
void bfs(int u, int cc)
{
    queue<int> q;
    int v;
    viz[u]=cc; q.push(u);
    while(!q.empty())
    {
        u=q.front(); q.pop();
        for(it=g[u].begin();it!=g[u].end();it++)
        {
            v=*it;
            if(!viz[v])
            {
                viz[v]=cc;
                q.push(v);
            }
        }
    }
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int n,m,u,v,i,cc;
    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);
    cc=0;
    for(i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            ++cc;
            bfs(i,cc);
        }
    }
    printf("%d", cc);
    return 0;
}