#include<bits/stdc++.h>
using namespace std;

int a[1005][1005], n, m, viz[1005], cnt;
ofstream out("dfs.out");
void citire()
{
    ifstream in("dfs.in");


    in>>n>>m;
    int i, x, y;
    for(int i = 1; i <=m; i++)
    {
        in>>x>>y;
        a[x][y] = a[y][x] = 1;
    }
}

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

int main()
{
    citire();
    int i;
    for(int i = 1; i <= n; i++)
        if(!viz[i])
        {
            cnt++;
            DFS(i);
        }
    out<<cnt;
    return 0;
}