#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n,m,viz[100001],mat[100001][100001];

void dfs(int x) {
    viz[x] = 1;
    for (int i = 1; i <= n; i++) {
        if (viz[i] == 0 && mat[x][i] == 1) {dfs(i);}
    }
}

int main() {
    int c=0;
    fin>>n>>m;
    while(m--) {
        int x,y;
        fin>>x>>y;
        mat[x][y]=mat[y][x]=1;
    }
    for(int i=1;i<=n;i++) {
        if(viz[i]==0) {dfs(i);c++;}
    }
    fout<<c;
    return 0;
}