#include <cstdio>
#include<vector>
#define maxn 200010
using namespace std;

FILE *f=fopen("dfs.in","r");
FILE *g=fopen("dfs.out","w");
vector <int> G[maxn];
int v[maxn],n,m,x,y,nr;
void search(int nod){
    v[nod]=1;
    while(G[nod].size()>0){
        int x=G[nod][0];
        G[nod].erase(G[nod].begin());
        if(v[x]==0)
            search(x);
    }
}
int main()
{
    fscanf(f,"%d%d",&n,&m);
    for(int i=1;i<=m;i++){
        fscanf(f,"%d%d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(int i=1;i<=n;i++){
        if(v[i]==0)
        search(i),nr++;
    }
    fprintf(g,"%d",nr);
    return 0;
}