#include <fstream>
#define NMAX 1001
using namespace std;

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

int n, m, x, y, ans, a[NMAX][NMAX], visited[NMAX];

void citire(){
    fin>>n>>m;
    for(int i = 1; i <= m; ++i){
        fin>>x>>y;
        a[x][y] = a[y][x] = 1;
    }
}

void dfs(int node){
    visited[node] = 1;
    ++ans;
    for(int i = 1; i <= n; ++i){
        if(a[node][i] && !visited[i]){
            dfs(i);
        }

    }
}

int main(){
    citire();
    dfs(1);
    fout<<ans<<'\n';
    return 0;
}