#include <iostream>
#include <fstream>
#include <stack>
using namespace std;
ifstream fin ("dfs.in");
ofstream fout("dfs.out");
stack <int> A[100005];
bool BR[100005];
void DFS(int x)
    {
        int k;
        BR[x]=1;
        while(!A[x].empty())
            {
                k=A[x].top();
                A[x].pop();
                DFS(k);
            }
    }
int main()
{
    int n,m,i,x,y,rez=0;
    fin>>n>>m;
    for(i=1;i<=m;i++)
        {
            fin>>x>>y;
            A[x].push(y);
            A[y].push(x);
        }
    for(i=1;i<=n;i++)
        if(BR[i]==0)
        {
            DFS(i);
            rez++;
        }
    fout<<rez<<'\n';
    fin.close();
    fout.close();
    return 0;
}