#include <bits/stdc++.h>

using namespace std;

ifstream in("dfs.in");
ofstream out("dfs.out");

int n,m,verif[100001],rez[100001],s;
vector <int> v[100001];

void dfs(int x)
{
    verif[x]++;
    for(int i = 0;i < v[x].size();i++)
        if(verif[v[x][i]] == 0)
            dfs(v[x][i]);
}

int main()
{
    in>>n>>m;
    for(int i = 1;i<=m;i++)
    {
        int x,y;
        in>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    /*for(int i = 1;i<=n;i++)
    {
        for(int j = 0;j < v[i].size();j++)
            cout<<v[i][j]<<" ";
        cout<<"\n";
    }*/
    for(int i = 1;i<=n;i++)
    {
        if(rez[i] == 0)
        {
            s++;
            for(int j = 1;j<=n;j++)
                verif[j] = 0;
            dfs(i);
            for(int j = 1;j<=n;j++)
            {
                if(verif[j] == 1)
                    rez[j]++;
            }
        }
    }
    out<<s;

    return 0;
}