#include<bits/stdc++.h>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n, m, x, y, nr;
vector<int> v[200001];
int viz[200001];
void dfs(int nod)
{
    viz[nod] = 1;
    for(int i = 0; i < v[nod].size(); i++)
        if(viz[v[nod][i]] != 1)
            dfs(v[nod][i]);
}
int main()
{
    f>>n>>m;
    for(int i=1; i <= m; i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i = 1; i <= n; i++)
        if(viz[i] != 1)
        {
            nr++;
            dfs(i);
        }
    g << nr;
}