#include<cstdio>
#include<vector>
using namespace std;
vector<int> v[100001];
int n,m,viz[100001];
void citire()
{
    freopen("dfs.in","r",stdin);
    int x,y;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
}
void DF(int x)
{
    viz[x]=1;
    for(vector<int>::iterator it=v[x].begin();it!=v[x].end();++it)
        if(viz[*it]==0) DF(*it);
}
int main()
{
    citire();
    int k=0;
    for(int i=1;i<=n;i++)
        if(viz[i]==0)
        {
            k++;
            DF(i);
        }
    freopen("dfs.out","w",stdout);
    printf("%d",k);
    return 0;
}