#include <bits/stdc++.h>

using namespace std;
vector < int > nod[200005];
int m,n,i,x,y;
bool viz[200005];
void DFS(int  s){
    viz[s]=1;
    for(i=0;i<nod[s].size();i++)
    if(viz[nod[s][i]]==0) DFS(nod[s][i]);
}
int main()
{   ifstream cin;
    cin.open("dfs.in");
    ofstream cout;
    cout.open("dfs.out");
    cin>>n>>m;
    for(i=1;i<=m;i++){
        cin>>x>>y;
        nod[x].push_back(y);
        nod[y].push_back(x);
    }
    int root =1,ans=1;
    DFS(root);
    for(i=1;i<=n;i++)
    if(viz[i]==0){
        DFS(i);
        ans++;
    }
    cout<<ans;
    return 0;
}