#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
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)
{
    int v;
    queue<int>q;
    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,cc;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&u,&v);
        G[u].push_back(v);
        G[u].push_back(u);
    }
    viz.assign(n+1,0);
    cc=0;
    for(int i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            ++cc;
            bfs(i,cc);
        }
    }
    printf("%d",cc);
    return 0;
}