#include<cstdio>
#include<vector>
using namespace std;

vector <int> v[100005];
vector <int> a;

char marc[100005];

void dfs (int x)
{
    int st=0,dr=0,i;
    a.erase(a.begin(),a.end());
    a.push_back(x);
    marc[x]=1;
    while (st<=dr)
    {
        for (i=0; i<v[a[st]].size(); i++)
            if (!marc[v[a[st]][i]])
            {
                a.push_back(v[a[st]][i]);
                marc[v[a[st]][i]]=1;
            }
        st++;
    }
}

int main ()
{
    int n,m,i,cont=0,x,y,j;
    //freopen("dfs.in","r",stdin);
    //freopen("dfs.out","w",stdout);
    scanf("%d%d",&n,&m);
    for (i=1; i<=m; i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (i=1; i<=n; i++)
        if (!marc[i])
        {
            dfs(i);
            cont++;
        }
    printf("%d\n",cont);
    return 0;
}