#include <bits/stdc++.h>

using namespace std;

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

bool a[10005][10005],viz[10005];
int n,m,cnt;

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

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