#include <bits/stdc++.h>

using namespace std;

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

#define MAX_N 100000
bool verif[MAX_N];

vector<int> graf[MAX_N];

queue <int> Q;

void dfs()
{
    while(!Q.empty())
    {
        int node = Q.front();
        Q.pop();
        for(int i = 0; i < graf[node].size(); ++i)
        {
            if(!verif[ graf[node][i] ])
            {
                verif[ graf[node][i] ] = 1;
                Q.push( graf[node][i] );
            }
        }
    }
}

int main()
{
    int n, m, x, y, ans = 0;
    in >> n >> m;
    for(int i = 0; i < m; ++i)
    {
        in >> x >> y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    for(int i = 0; i < n; ++i)
    {
        if(!verif[i])
        {
            Q.push(i);
            dfs();
            ans++;
        }
    }
    out << ans;
    return 0;
}