#include<cstdio>
#include<vector>

#define N_MAX 100010
using namespace std;

vector <int> G[N_MAX];

bool sel[100010];
int sol=0,n,i;

inline void df(int x)
{
    int i;
    vector <int> :: iterator it;
    for (it=G[x].begin();it<G[x].end();it++)
        if (!sel[*it])
            {
                sel[*it]=true;
                df(*it);
            }
}

inline void load()
{
    int x,y,i,m;
    scanf("%d%d",&n,&m);
    for (i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    load();
    for (i=1;i<=n;i++)
        if (!sel[i])
            {
                sol++;
                df(i);
            }
    printf("%d\n",sol);
    fclose(stdin);
    fclose(stdout);
    return 0;
}