#include <fstream>
#include <vector>

using namespace std;

ifstream cin("dfs.in");
ofstream cout("dfs.out");

const int N=100001;

vector <int> a[N];
int n,m,viz[N],s;

void citire(){
    cin >> n >> m;
    int i,x,y;
    for(i=0; i<m; i++){
        cin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    cin.close();
}

void dfs(int x){
    viz[x] = true;
    int i,y;
    for(i=0; i<a[x].size(); i++){
        y=a[x][i];
        if(!viz[y]){
            dfs(y);
        }
    }
    s++;
}

int main()
{
    citire();
    dfs(1);
    cout << s;
    return 0;
}