#include <iostream>
#include <fstream>

using namespace std;

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

int n, m, x, y, a[100001][100001];
int ans, viz[100001];

void dfs(int nod)
{
    viz[nod] = ans;
    for(int i=1; i<=n; i++)
        if(a[nod][i] == 1 && viz[i] == 0)
            dfs(i);
}

int main()
{
    in>>n>>m;
    for(int i=1; i<=m; i++)
    {
        in>>x>>y;
        a[x][y] = a[y][x] = 1;
    }
    for(int i=1; i<=n; i++)
    {
        if(viz[i] == 0)
        {
            ans++;
            dfs(i);
        }
    }
    out<<ans;
    return 0;
}