#include <cstdio>
#include <vector>
using namespace std;
int i,j,m,nr,n,x,y;
bool ok[100000];
vector <int> v[100000];
void DF(int x)
{
    int i,k;
    vector <int> ::iterator it;
    if(!ok[x]) ok[x]=true;
    for(it=v[x].begin(); it!=v[x].end(); it++)
    {
        if(!ok[*it]) DF(*it);
    }

}
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++)
    if(!ok[i]) {DF(i);nr++;}
    printf("%d",nr);
    return 0;
}