#include<cstdio>
#include<vector>
#define Max 100005

using namespace std;
int k=0,i,j,n,m,x,y,L[Max];
bool viz[Max];
vector<int> v[Max];
void dfs(int nod)
{
    viz[nod]=true;
    for(j=0;j<L[nod];++j) if(!viz[v[nod][j]]) dfs(v[nod][j]);
}
int main()
{
    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) L[i]=v[i].size();
    for(i=1;i<=n;++i)
        if(!viz[i])
        {
            ++k;
            dfs(i);
        }
    printf("%d\n",k);
    return 0;
}