#include<fstream>
#include<stack>
#include<vector>
#define NMAX 100005

//in-out
std::ifstream f("dfs.in");
std::ofstream g("dfs.out");

//data
std::vector<int>G[NMAX];
std::stack<int>st;
std::vector<bool> visited(NMAX);
int n, m;

void readData(){
    f >> n >> m;
    int x, y;
    for(int i = 0; i<m; i++){
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void dfs(int start){
    visited[start] = true;
    for(const auto& adj : G[start]){
        if(!visited[adj]){
            dfs(adj);
        }
    }
}

int connectedComponents(){
    int nrComps = 1;
    dfs(1);
    for(int i = 2; i<=n; i++){
        if(!visited[i]){
            nrComps += 1;
            dfs(i);
        }
    }
    return nrComps;
}

int main(){
    readData();
    g << connectedComponents();
    return 0;
}