#include <bits/stdc++.h>
#define cin in
#define cout out
using namespace std;

const string file_name("dfs");

ifstream in(file_name + ".in");
ofstream out(file_name + ".out");

int n,m,x,y,cnt;
unordered_map<int,vector<int>> M;
bitset<100005> v;

void read()
{
    cin>>n>>m;

    while(m--)
    {
        cin>>x>>y;
        M[x].push_back(y);
        M[y].push_back(x);
    }
}

void dfs(int k)
{
    if(!v[k])
    {
        v[k]=1;
        for(auto x: M[k])
            dfs(x);
    }
}

int main()
{
    read();
    for(int i=1;i<=n;i++)
        if(!v[i])
            dfs(i),cnt++;
    cout<<cnt;
    return 0;
}