#include <stdio.h>
#include <vector>
#include <deque>
#include <bitset>

using namespace std;
FILE *f,*g;

deque <int> q;
vector <int> graph[100002];
//bitset <100002> fr;
bool fr[100002];

void dfs(int nod)///dfs varianta iterativa
{
    q.push_back(nod);
    fr[nod]=1;
    while(!q.empty())
    {
        nod=q.front();
        for(int i=0;i<graph[nod].size();++i)
        {
            if(!fr[graph[nod][i]])
                fr[graph[nod][i]]=1,q.push_back(graph[nod][i]);
        }
        q.pop_front();
    }
}
int main()
{
   int m,n,ss=0;
   f=fopen("dfs.in","r");
   g=fopen("dfs.out","w");
   fscanf(f,"%d %d",&n,&m);
   int x,y;
   for(int i=1;i<=m;++i)
   {
       fscanf(f,"%d %d",&x,&y);
       graph[x].push_back(y);
       graph[y].push_back(x);
   }
   for(int i=1;i<=n;++i)
        if(!fr[i])
          ++ss,dfs(i);
    fprintf(g,"%d\n",ss);
    fclose(f);
    fclose(g);
    return 0;
}